University of South FloridaScholar Commons

Graduate Theses and Dissertations Graduate School

4-6-2006

The Mucilage of Opuntia Ficus Indica: A Natural,Sustainable, and Viable Water TreatmentTechnology for Use in Rural Mexico for ReducingTurbidity and Arsenic Contamination in DrinkingWaterKevin Andrew YoungUniversity of South Florida

Follow this and additional works at: http://scholarcommons.usf.edu/etd

Part of the American Studies Commons

This Thesis is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in GraduateTheses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact scholarcommons@usf.edu.

Scholar Commons CitationYoung, Kevin Andrew, "The Mucilage of Opuntia Ficus Indica: A Natural, Sustainable, and Viable Water Treatment Technology forUse in Rural Mexico for Reducing Turbidity and Arsenic Contamination in Drinking Water" (2006). Graduate Theses and Dissertations.http://scholarcommons.usf.edu/etd/3832

The Mucilage of Opuntia Ficus Indica: A Natural, Sustainable, and Viable Water

Treatment Technology for Use in Rural Mexico for Reducing Turbidity and Arsenic

Contamination in Drinking Water

by

Kevin Andrew Young

A thesis submitted in partial fulfillment of the requirements for the degree of

Master of Science in Chemical Engineering Department of Chemical Engineering

College of Engineering University of South Florida

Major Professor: Norma Alcantar, Ph.D. Babu Joseph, Ph.D.

Thomas Pichler, Ph.D. Peter Stroot, Ph.D.

Ryan Toomey, Ph.D. Maya Trotz, Ph.D.

Date of Approval: April 6, 2006

Keywords: flocculant, cactus, nopal, prickly pear, mucilage, green engineering, sustainability

© Copyright 2006, Kevin Andrew Young

Dedication

The dedications of a thousand theses would not suffice as a thank you to

my loving parents, Mr. Jeffery B. Young and Mrs. Nancy S. Young, for their

sacrifice, hard work, understanding and support for my goals. The successes I

have experienced would not have been possible without them selflessly adopting

my personal goals as their own. For that, I am eternally grateful.

This work is also dedicated to the memories of those lives lost from

arsenic poisoning due to contaminated drinking water.

Acknowledgements

I am forever indebted to my major professor, Dr. Norma Alcantar, for her

undying patience, dedication, care, concern, and assistance. I also am intensely

grateful for each and every instance where she prioritized her graduate students

before her own professional and personal obligations. This thesis also would not

have been possible without the following contributions.

Dr. Alessandro Anzalone for his help in the beginning stages of the

project.

USF STARS (Students, Teachers, and Resources in the Sciences) for

fellowship funding and invaluable elementary science classroom

experience; National Science Foundation (NSF) Grant No. 0139348.

NSF for providing funding for this project; NSF Grant No. 0442977.

Dr. Thomas Pichler, Dr. Maya Trotz, and their students for their support in

the use of laboratory equipment.

My heroes: Ms. Sabrina Gates, Mrs. Sharyn Gibson, and Mr. Dan

McFarland, for being infinitely more than high school teachers.

Kristina Dearborn for being a flawless role model and keeping me

grounded in an atmosphere where reality can be fleeting.

My mahal for love, encouragement, and reaffirming that Chemical

Engineering is a fulfilling passion but could never satisfy as a lifestyle.

i

Table of Contents

List of Tables iv List of Figures v Abstract vii Chapter One: Introduction 1 1.1. Thesis Structure 1 1.2. Introduction 2 1.3. Turbidity and Arsenic Poisoning 2 1.4. Introduction to this Study 5 1.5. Significance of this Study 6 1.6. Research Goals 7 1.6.1. Goal One: Turbidity Removal 7 1.6.2. Goal Two: Arsenic Removal 7 1.6.3. Goal Three: Chemical Characterization 7 1.6.3. Goal Four: Cultural Sensitivity 8 1.6.4. Goal Five: Insights into Interdisciplinary Collaboration 8 1.7. Delimitations and Limitations of this Study 8 Chapter Two: Flocculation, Arsenic Removal, and the Socio-Cultural Aspects of Water Quality 9 2.1. Water Treatment: Turbidity 9 2.2. Water Treatment: Arsenic Removal 13 2.3. Investigated Modes of Arsenic Remediation 19 2.3.1. Bangladesh and West Bengal, India 19 2.3.2. Mexico 32 Chapter Three: Water Contamination in Four Mexican Communities 38 3.1. Zimapán 40 3.2. Region Lagunera 41 3.3. Hierve el Agua 41 3.4. Temamatla 42 3.5. Socio-Cultural Impact Assessment in Temamatla 43 3.6. Implications for This Project 45

ii

Chapter Four: The Mexican Cactus as a Natural Technology for Water Treatment 47 4.1. Current Options: Natural Technologies 47 4.2. Proposed Source of Natural Flocculant: Opuntia ficus-indica 49 4.2.1. Current Uses 50 4.3. The Mucilage of Opuntia ficus-indica 52 4.3.1. Chemical Composition 52 4.3.2. Extraction Techniques 54 4.3.3. Current Applications 57 Chapter Five: Physical and Chemical Analytical Methods 58 5.1. Mucilage Characterization: Raman Spectroscopy 58 5.2. Turbidity 58 5.2.1. Cylinder Tests 58 5.2.2. Jar Tests 59 5.2.3. Light Scattering 59 5.3. Arsenic Removal 59 5.3.1. Hydride Generation – Atomic Fluorescence Spectroscopy 59 5.3.2. Atomic Absorption (AA) Spectroscopy 60 Chapter Six: Experimental Procedures 62 6.1. Turbidity Experiments 62 6.1.1 Materials 62 6.1.2. Cylinder Test Procedure 63 6.1.3. Jar Test Procedure 64 6.2. Arsenic Removal Experiments 66 6.2.1. Materials 66 6.2.2. Single Dose Method Procedure 67 6.2.3. Optimization Procedure 68 Chapter Seven: Results and Discussion 70 7.1. Comparison of Extracts: Chemical Composition 70 7.2. A Comparison of Extracts: Flocculation 73 7.2.1. Settling Rate 73 7.2.2. Residual Turbidity 77 7.3. Gelling Extract: Arsenic Removal Efficiency 79 7.3.1. Single Dose Method 79 7.3.2. Optimization 84 7.4. Cultural Sensitivity 85 7.5. Interdisciplinary Collaboration 87 Chapter Eight: Conclusions and Future Work 91 8.1. Summary of Findings 91 8.2. Future Work 93 8.2.1. Mucilage Extraction 93

iii

8.2.2. Flocculation 94 8.2.3. Arsenic Removal 94 8.2.4. Filter Design 95 8.2.5. Temamatla Implementation 95 8.3. Final Remarks 95 References 96 Appendices 107 Appendix A: Cylinder and Jar Tests Sample Dosage Schemes 108 Appendix B: Material Safety Data Sheets 109 B.1. Aluminum Sulfate 109 B.2. Arsenic(III) Oxide 117 B.3. Arsenic (V) Oxide 126 B.4. Arsenic Standard Solution 135 B.5. Kaolin 143 B.6. Nickel Nitrate 150 B.7. Nitric Acid 158 B.8. Sodium Hdyroxide 159

List of Tables

Table 1: Granular Media Filter Advantages and Disadvantages. 11 Table 2: A Comparison of Filter Types for the Reduction of Turbidity in

Drinking Water. 13 Table 3: Contamination in Four Mexican Communities. 40 Table 4: Differences in Detected Mucilage Properties: Molecular Weight And Sugar Content. 53 Table 5: Reagents Used in Flocculation Experiments. 62 Table 6: Equipment and Instruments Used in Flocculation Experiments. 63 Table 7: Reagents Used in Arsenic Removal Experiments. 66 Table 8: Equipment and Instruments Used in Arsenic Removal Experiments. 66 Table 9: Flocculant Doses for 100 ml Graduated Cylinder Tests from Prepared 1 g L-1 Stock Solutions of Flocculants. 108 Table10: Flocculant Doses for Each 0.5 L Jar Test Compartment from Prepared 1 g L-1 Stock Solutions of Flocculants. 108

iv

List of Figures

Figure 1: Precipitation/Coprecipitation Process. 15 Figure 2: Membrane Pore Sizes Compared to Sizes of Various Water

Contaminants. 16 Figure 3: Adsorption Column with Sorbent. 17 Figure 4: Model of a PRB. 18 Figure 5: Schematic of the Stevens Institute Technology Bucket Treatment Units. 25 Figure 6: Schematic of the DPHE-Danida Arsenic Mitigation Pilot Project Fill And Draw Units. 26 Figure 7: Schematic of Arsenic Removal Units Attached to a Tubewell in West Bengal, India. 27 Figure 8: Mexican Communities Surveyed for Contaminated Water. 39 Figure 9: Typical Household Water Storage and Usage Area for Low-Income Families in Temamatla. 43 Figure 10: Schematic of a Typical Microbiological Arsenic Treatment Unit. 49 Figure 11: An Example of Opuntia Growing as a Tree in Mexico. 50 Figure 12: McGarvie and Parolis' Proposed Mucilage Structure, Taken from Sáenz, 2004. 54 Figure 13: Modified Goycoolea and Cárdenas Extraction Method. 56 Figure 14: The Matching Spectra of CE and NE. 71 Figure 15: The Spectral Differences Between GE and NE. 72 Figure 16: Poly(ethyl cyanoacrylate) and Poly(ethyl acrylamide). 72

v

Figure 17: Flocculation Rates Comparison. 74 Figure 18: GE Compared To Al2(SO4)3. 74 Figure 19: The Effect of Dose on the Settling Rates of GE, CE, and NE. 75 Figure 20: A Comparison Showing the Differences in the Linear Portion of Settling. 76 Figure 21: Residual Turbidity of the Mucilages GE And CE. 77 Figure 22: Residual Turbidity of Al2(SO4)3, GE, and CE in a Low Dose Region. 78 Figure 23: Results of the Single Dose Arsenic Tests. 79 Figure 24: Single Dose Experiments to Elicit the Effect of pH on As Removal. 81 Figure 25: Average Gain in Arsenic Concentration Resulting from pH

Experiment. 82 Figure 26: Results of the Tri-Level Arsenic Distribution Experiment. 83 Figure 27: Solid Particles Observed In High Concentration As and GE Systems. 84 Figure 28: Results of the Optimization Experiments Illustrating the

Importance of Settling Time. 85

vi

vii

The Mucilage of Opuntia Ficus Indica: A Natural, Sustainable, and Viable

Water Treatment Technology for Use in Rural Mexico for Reducing

Turbidity and Arsenic Contamination in Drinking Water

Kevin Andrew Young

ABSTRACT

The use of natural environmentally benign agents in the treatment of

drinking water is rapidly gaining interest due to their inherently renewable

character and low toxicity. We show that the common Mexican cactus produces

a gum-like substance, cactus mucilage, which shows excellent flocculating

abilities and is an economically viable alternative for low-income communities.

Cactus mucilage is a neutral mixture of approximately 55 high-molecular weight

sugar residues composed basically of arabinose, galactose, rhamnose, xylose,

and galacturonic acid. We show how this natural product was characterized for

its use as a flocculating agent. Our results show the mucilage efficiency for

reducing arsenic and particulates from drinking water as determined by light

scattering, Atomic Absorption and Hydride Generation-Atomic Fluorescence

Spectroscopy. Flocculation studies proved the mucilage to be a much faster

flocculating agent when compared to Al2(SO4)3 with the efficiency increasing with

mucilage concentration. Jar tests revealed that lower concentrations of mucilage

provided the optimal effectiveness for supernatant clarity, an important factor in

viii

determining the potability of water. Initial filter results with the mucilage

embedded in a silica matrix prove the feasibility of applying this technology as a

method for heavy metal removal. This project provides fundamental, quantitative

insights into the necessary and minimum requirements for natural flocculating

agents that are innovative, environmentally benign, and cost-effective.

1

Chapter One

Introduction

1.1. Thesis Structure

This document will serve as an introduction to a possible water treatment

method for turbidity reduction and arsenic remediation using Opuntia ficus-indica

(OFI) mucilage as a natural material. Chapter One serves as an overall

introduction to the project. Chapter Two outlines current accepted turbidity

reduction and arsenic removal technologies and analyzes remediation

technologies implemented in Bangladesh, West Bengal, India and Mexico.

Chapter Three introduces the four Mexican communities surveyed for water

contamination and describes the results of socio-cultural impact assessment in

Temamatla, Mexico that helped to shape the goals of this project. Chapter Four

is an introduction to natural methods of water treatment and to the natural

treatment method analyzed in this study, OFI mucilage. Analytical and

experimental methods are detailed in Chapters Five and Six while results are

discussed in Chapter Seven. Chapter Eight serves as conclusions and

recommendations for future work.

2

1.2. Introduction

Water is a resource essential for life, and water quality commands much

attention from the world community. Access to clean water varies with

geography, economics, politics, and culture; however, the worldwide community

agrees that all of Earth’s citizens deserve access to the planet’s most essential

resource. Many people are still affected by contaminated, unhygienic drinking

water, especially in developing countries. There are about 1.1 billion people in

the world without access to clean water. It has been suggested that household

water treatment will be the critical path toward improved health due to the

relatively slow process of designing, installing, and delivering piped water to

communities [1].

The source of contaminants in drinking water can run the gamut from

chemical to biological to geological in such forms as man-made pollution,

stagnation or bacterial contamination, or natural sources of harmful minerals.

There are a myriad of guidelines outlining requirements for drinking water

contaminant concentrations but only two will be addressed in this thesis: turbidity

(particle removal) and arsenic.

1.3. Turbidity and Arsenic Poisoning

Drinking water turbidity, or cloudiness, affects a community’s opinion on

the safety of certain water sources. The visual aspect of cloudy water is enough

to discourage any consumer from drinking water from a faucet, well, spring, or

any other source. Turbidities less than 5 NTU (nephelometer turbidity units) are

3

considered to be “safe” by most consumers, but the World Health Organization

(WHO) unofficially considers 0.1 NTU to be the maximum turbidity allowed for

disinfection [2].

The turbidity in any water source is due to solids suspended in the water

column. These solids result from a variety of sources including resuspended

sediments, inadequate filtration, inorganic particles, or biological sources. All

sources of turbidity will decrease the effectiveness of the disinfection process

because particles promote the growth of microorganisms and protect them from

the disinfecting agents. Microbial contamination in drinking water can cause

many hygiene-related illnesses such as diarrhea and infectious diseases [3].

Turbidity reduction can vastly improve the effectiveness of disinfection methods

[2]. Although WHO unofficially considers 0.1 NTU as a maximum turbidity

allowance, they currently have no guidelines on drinking water turbidity [2].

The prevalence of arsenic in drinking water is variable, depending on

water source and location. Arsenic can be found in rainwater, surface waters,

and groundwaters [4]. The latter poses the greatest health risk to humans due to

direct ingestion of arsenic-contaminated well waters [4]. The WHO recognized

the risks of ingesting arsenic-contaminated ground water in 1958 and, therefore,

in 1993 they reduced the recommended guidelines from 0.05 mg L-1 (50 µg L-1)

to 0.01 mg L-1 (10 µg L-1). The WHO based this guideline on current detection

limits due to equipment diagnostic abilities [5].

Natural arsenic sources include minerals, rocks, soils, sediments, and the

atmosphere where arsenic is transported due to industrial effluents, fossil-fuel

4

combustion products, and natural volcanic emissions. Arsenic is not considered

a natural constituent of water, so when it is found it is due to several mobilization

mechanisms such as physical, chemical, or biological interactions. Mineral-water

interactions are often enough to mobilize arsenic through a solid-solution

interaction like precipitation-dissolution, adsorption-desorption, or coprecipitation

interactions [4].

Adsorption-desorption is the primary arsenic mobilizing interaction in many

environments. The As adsorption-desorption potential is a function of many

different variables including pH, redox potential, As concentration, the

concentration of competing and complexing ions, aquifer mineralogy, reaction

kinetics, and biological activity [6]. The mechanism relies upon a surface

adsorption phenomenon, implying the presence of suspended solids in the

groundwater source. Adsorption-desorption contributing aquifer solids include

iron oxides, aluminum oxides, oxyhydroxides, manganese oxides, silica oxides,

aluminosilicate clay minerals, carbonate minerals, aquifer solids covered with an

adsorbed layer of humic acids, and soil and sediment particles [6]. This

dependence upon the presence of solids in groundwater for the occurrence of

adsorption-desorption arsenic mobilization supports a need for the simultaneous

reduction of turbidity and mobilized arsenic.

Health effects resulting from exposure to inorganic arsenic depend on the

exposure amount and exposure duration. Months of exposure to arsenic

concentrations of 0.04 mg kg-1 day-1 (considered high) can result in health effects

that are usually reversible including diarrhea and cramping, anemia, leukopenia,

5

and peripheral neuropathy; chronic exposure to high doses for 0.5 to 3 years can

result in skin effects like hyperpigmentation. Hyperpigmentation can also be

found in those exposed to long durations of low doses (5-15 years). Many other

detrimental effects to health are linked to chronic arsenic ingestion including

vascular diseases, cardiovascular diseases such as hypertension, diabetes

mellitus, immune system disease, respiratory diseases, developmental and

reproductive effects, neurological effects, and hepatotoxic effects [7]. The

occurrence of some skin, bladder, and lung cancers have also been linked to

arsenicosis [8], or the exposure to arsenic over a long period of time [9].

1.4. Introduction to this Study

The overall project is a complex interdisciplinary, international research

project merging engineering principles, scientific explorations, and socio-cultural

investigations. As such, a network of researchers from different disciplines and

countries was assembled to efficiently elucidate a solution for this complex

problem of drinking water quality facing Mexican communities. Relationships

were formed between investigators in the U.S. and collaborators in Mexico, as

well as across the engineering, geology, physical chemistry, and anthropology

disciplines. Chemical engineers, geologists and hydrologists, and

anthropologists from the University of South Florida in Tampa have combined

with counterparts at Mexico’s three most important and internationally recognized

research institutions to create a successful team of collaborators.

6

The study represented by this thesis is a contribution to the overall goals

of the project. It includes culturally sensitive engineering and scientific

investigations into the flocculation and arsenic removal properties of the mucilage

of the cactus OFI. It also includes insights gathered with respect to the success

of interdisciplinary collaborations.

1.5. Significance of this Study

The WHO recognizes a need for investigations into new low-cost physical

and physical-chemical techniques to remove turbidity from household water [10].

This study seeks to uncover an innovative new technology that can be

implemented for turbidity reduction and arsenic removal in areas of

contamination where citizens are economically unable to invest in the

established, accepted, and costly methods of drinking water treatment. In doing

so, individuals exposed to arsenic contamination through ingested groundwater

will benefit from an inexpensive, easy to implement, and natural technology that

will be a socially, culturally, environmentally, and scientifically appropriate way to

improve their quality of life and health. In the process, a scientific explanation of

a naturally observed phenomenon will be provided: the ability of the cactus OFI

to reduce turbidity when added to cloudy waters. Also, investigations into the

ability of OFI extracts to remove heavy metals from water will uncover new

scientific pathways for research into natural arsenic removal methods.

WHO recognizes the social applicability of drinking water treatment

methods as an essential component in their effectiveness [3]. By adhering to

7

recommended guidelines for social applicability of water remediation projects,

this research will also provide a case study in the use of socio-cultural impact

assessment for the shaping of project methods and goals.

1.6. Research Goals

1.6.1. Goal One: Turbidity Removal

This project seeks to determine the scientific basis for the use of OFI as a

natural flocculant in reducing drinking water turbidity. Specifically, the mucilage

of the OFI will be investigated as the primary source of the flocculation process.

1.6.2. Goal Two: Arsenic Removal

It is suspected that the mucilage of the OFI will not only be active in

reducing turbidity, but also in removing arsenic from contaminated waters. This

project will determine the effectiveness of the mucilage in the reduction of arsenic

concentration, which will be a contribution to the final project goal of assessing

mucilage effectiveness in the removal of heavy metals including arsenic,

selenium, cadmium, as well as other harmful metals.

1.6.3. Goal Three: Chemical Characterization

The third goal of this project is to determine the composition of the

mucilage in order to determine the source of its flocculation ability. Also, to

determine the mechanism by which the mucilage removes suspended solids and

arsenic.

8

1.6.3. Goal Four: Cultural Sensitivity

The third goal of this project is the overreaching umbrella of cultural

sensitivity. The turbidity reduction and arsenic removal technology developed

must be implementable, acceptable, and useful in the houses or towns of low-

income communities.

1.6.4. Goal Five: Insights into Interdisciplinary Collaboration

The final goal of this project is to extract useful information in the form of

protocols and suggestions for success applicable to interdisciplinary

collaborations in related studies.

1.7. Delimitations and Limitations of this Study

It has been suggested that technologies developed for implementation in

low-income, indigenous communities should be simple and easy to produce,

inexpensive, employ native or easily accessible materials, and have a rural focus

[11]. These guidelines are the design boundaries for this project. This study also

seeks to determine the efficiency of the mucilage of OFI in water treatment in

order to determine the least work-intensive, most culturally sensitive way to

implement Opuntia as a natural method for water treatment in Mexican

communities.

The mucilage can be separated into different concentrations of sugars.

Depending on the chemical composition, it is easy to extract three substances

that can be tested to treat water. As a result, only these three extracted

chemicals were utilized in the water treatment analyses described herein.

9

Chapter Two

Flocculation, Arsenic Removal, and the Socio-Cultural Aspects of

Water Quality

2.1. Water Treatment: Turbidity

The World Health Organization (WHO) considers treating biological

contamination of turbid water in the home a challenge due to the effect of

turbidity in decreasing access to microbes by inactivation mechanisms such as

UV radiation from lamps or sunlight [10]. The WHO maintains that,

“There is a need to investigate, characterize and implement

physical and physical-chemical technologies for practical and low

cost pre-treatment of treatment of household water prior to

chlorination, solar disinfection with UV plus heat and UV

disinfection with lamps [1].”

The WHO currently recognizes four different categories of turbidity-reduction

mechanisms (listed below) as potential areas for investigation [1].

• Settling or plain sedimentation

• Filtering with fibers, cloth, or membranes

• Filtering with granular media

• Slow sand and Biosand filters

10

Plain Sedimentation Settling, or plain sedimentation, is simply allowing

cloudy water sit for a period of time and letting gravity settle the particulates

present. Decanting or ladling out the supernatant leaves the sediment behind.

This can be done with any size of water vessel and has been practiced since

ancient times [1]. This process has the advantage of being a low-cost way to

reduce suspended solids and some microbes, and is generally recommended as

pre-treatment before disinfection. Unfortunately, sedimentation will not remove

clays and smaller solid particles, nor will it remove smaller microbes [1]. Also,

the settling length for some solids can be as long as two days [1].

Membrane Filter Filtration is another technology that has been in use since

ancient times. The WHO recognizes three types of filtering: membranous,

granular media, and slow sand and Biosand filters. Membrane filters include

filters made of compressed or cast fibers like cellulose papers or synthetic

polymer filters, spun threads or woven fabrics. Generally, filters are placed over

a water source and are used widely for point-of-use water supply systems.

Funnels are also used to pass water through the filters on which solids are

collected; a variation of this is the use of porous cartridges. These membrane

filters do not always remove all suspended solids or all microbial contamination

[1].

Granular Media The use of sand filters, or other porous granular media filters

are the most widely used physical water treatment technology on the community

11

level. Different technologies have been produced that include the use of different

granular media such as sand, anthracite, crushed sandstone, other soft rock, and

charcoal. These filters are designed to be used at the household level and

include bucket filters, drum filters, barrel filters, roughing filters (one or more

basins), and above or below grade cistern filters. Table 1 compares the different

granular media filters [1].

Table 1: Granular Media Filter Advantages and Disadvantages.

Filter Design Advantages Disadvantages

Bucket filter

• Use on a small scale at household level

• Simple • Can use local, low

cost media and buckets

• Simple to operate manually

• May require fabrication by user

• Initial education and training in fabrication and use needed

• Requires user maintenance

Barrel or drum filter

• Use on a small scale at household or community level

• Relatively simple • Can use local and

low cost media and barrels or drums

• Requires some technical knowledge for fabrication and use

• Initial education and training needed

Roughing filter

• Use on a small scale at community level

• Relatively simple • Can use local, low

cost construction material and media

• Less amenable to individual household use because of scaling

• Requires some technical knowledge for construction and use

12

Bucket filters consist of two buckets - one as a filter and the other as a

cistern. The filter bucket has holes drilled in the bottom and a layer several

centimeters thick of gravel, on top of which is placed an even thicker bed of sand

(0.1 to 1mm grain size). Water is poured through the filter bucket and collected

in the cistern bucket. The collected water has a low turbidity, but the sand must

be replaced often to avoid the buildup of biological contaminants. Bucket filters

are commercially available [1].

Drum or barrel filters are generally configured in a down-flow or up-flow

design. A 55-gallon drum is set up much like the filtering bucket in bucket filters.

Water is poured through the drum and a pipe at the bottom collects the clean

water. For the up-flow design, water is forced up through the bottom of the filter

bucket and discharged near the top. Different granular media can be used, even

combinations of sand and charcoal [1].

Roughing filters consist of a rectangular-shaped basin of different

compartments of granular media with decreasing particle size in the direction of

water flow. Water moves through the filter until non-turbid product is collected at

the end. This set-up requires frequent backwashing, requiring a certain amount

of skill or proper operation [1].

Everything from sponges to charcoal has been employed in the reduction

of turbidity for the apparent cleansing of drinking water. Biomass has also been

used as a filter medium. Filters have also been made of cotton, wool, linen,

pulverized glass, burnt rice hulls, and fresh coconut fibers [1]. Table 2 serves as

a comparison of the different types of filter media [1].

13

Table 2: A Comparison of Filter Types for the Reduction of Turbidity in Drinking Water.

Type of Filtration Media Ease of Use Effectiveness

(comments) Cost

Granular media, rapid rate depth

filters

Sand, gravel, diatomaceous

earth, coal, other

minerals

Easy to moderate

Moderate* (depends on microbe size

and pre-treatment)

Low to moderate

Slow sand filters Sand

Easy to moderate

(community use)

High** in principle but often low in

practice

Low to moderate

Vegetable and animal

derived depth filters

Coal, sponge, charcoal,

cotton, etc.

Moderate to difficult Moderate* Low to

moderate

Fabric, paper, membrane, canvas, etc.

filters

Cloth, other woven fabric,

synthetic polymers,

wick siphons

Easy to moderate

Varies from high to low (with pore size and

composition)

Varies: low for natural;

high for synthetics

* Moderate typically means 90-99% reductions of larger pathogens (Helminth ova and larger protozoans) and solids-associated pathogens, but low (<90%) reductions of viruses and free bacteria, assuming no pre-treatment. With pre-treatment (typically coagulation), pathogen reductions are typically >99% (high). **High pathogen reduction means >99%.

2.2. Water Treatment: Arsenic Removal

The US Environmental Protection Agency (USEPA) recognizes eight

different categories for arsenic treatment technologies applicable to groundwater

in their report, Arsenic Treatment Technologies for Soil, Waste, and Water [12].

They are as follows:

14

• Precipitation/Coprecipitation

• Membrane Filtration

• Adsorption Treatment

• Ion Exchange Treatment

• Permeable Reactive Barriers

• Electrokinetic Treatment

• Phytoremediation

• Biological Treatment

Precipitation/Coprecipitation This is the most frequently used method for

arsenic remediation in groundwater for both drinking water and wastewater. This

method has reduced levels below the current USEPA guideline of 0.01 mg L-1.

Also, it has the potential to reduce other contaminants that hinder the quality of

drinking water, including turbidity, iron, phosphate, manganese, fluoride, color,

and odor [13]. Precipitation/coprecipitation technologies include the use of a

chemical treatment leading to the precipitation or coprecipitation of a solid and

the subsequent separation of the solid from the water source. Chemicals used to

precipitate a solid include ferric chemicals such as salts and sulfates; sulfate

chemicals like ammonium, copper, and manganese sulfate; aluminum hydroxide,

lime, and a form of pH adjustment [12]. An example of a

precipitation/coprecipitation process is illustrated in Figure 1 [12].

Figure 1: Precipitation/coprecipitation Process.

Membrane Filtration This is a process used less frequently than

precipitation/coprecipitation processes although their solids removal efficiencies

are comparable. They are also associated with having higher operating costs.

Membrane filtration is a technology used mostly to treat groundwaters and is

characterized by processes including any one of the following: microfiltration,

ultrafiltration, nanofiltration, or reverse osmosis. Figure 2 illustrates the pore

sizes of different membrane technologies [13]. The applicability of this process

depends upon the quality of the feed stream. Suspended solids or any dissolved

solid with high molecular weight can potentially foul the membrane [12].

Depending upon feedwater quality, different pretreatment options must be

employed. Also, to increase arsenic removal efficiencies, prior treatment must

be performed to convert As(III) to As(V) since the As(V) tends to have a larger

ionic radius [12].

15

Figure 2: Membrane Pore Sizes Compared to Sizes of Various Water

Contaminants. Adsorption Adsorption methods are also used less frequently than

precipitation/coprecipitation although they also have similar removal efficiencies.

This technology includes any process where adsorption is the primary

mechanism employed for removal. Adsorption processes can use a combination

of precipitation/coprecipitation, ion exchange, and filtration technologies.

Generally, they involve a column with a bed of sorbent media through which

feedwater is passed. A variety of sorbents can be used including activated

alumina, activated carbon, copper-zinc granules; ferric-hydroxide or ferric-

hydroxide newspaper pulp; iron oxide coated sand or iron filings in sand, KMnO4

coated glauconite, surfactant-modified zeolite, and others [12, 13]. Adsorption

methods generally include regenerating the sorbent through a backwashing

16

method [12]. Pretreatment is also required for adsorption methods due to the

same factors affecting fouling in membrane methods [14, 15]. Figure 3 illustrates

a typical adsorption process [12].

Figure 3: Adsorption Column with Sorbent.

Ion Exchange Treatments employing ion exchange for arsenic removal are

very similar to the adsorption technique with respect to process configuration.

The difference is in the replacement of a sorbent with an ion exchange resin [12].

An ion exchange media is used consisting of either a strong or weak acid or base

in order to regenerate the resin after it is fouled with removed arsenic [16]. This

technology can provide effective arsenic removal in the range of <0.05 mg L-1 to

<0.01 mg L-1, but is used less frequently than precipitation/coprecipitation due to

the same process sensitivities effecting membrane filtration and adsorption

processes: tedious, skillful regeneration and high cost [12]. 17

Permeable Reactive Barrier A permeable reactive barrier (PRB) treatment

system is placed underground in the direction of groundwater flow, creating an in

situ arsenic treatment method. This is not a popular treatment technology but

has been used as a way to treat contaminated plumes of groundwater. It

consists of an underground wall, inside of which is a media that is reactive with

arsenic. Water passes through the wall and arsenic is immobilized. PRBs are

not effective in aquifers with high hydraulic conductivities or aquifers deeper than

70 feet. Also, PRB plugging with loose rock and sediments can hinder PRB

effectiveness. Figure 4 illustrates a generic PRB set-up [12].

Figure 4: Model of a PRB.

Electrokinetic The USEPA classifies electrokinetic arsenic treatment

methods as an emerging technology. This is a method applicable to not only

groundwater but also to soils. Essentially, electrodes are placed in soil or water

and a current is passed through the media to be treated. Metals in the form of

18

19

ions are attracted by the electric field to the electrodes where they are removed

[12]. Arsenic species present would have to be in ionic forms for this process to

be applicable. This technology is also only suitable to acid-soluble polar

compounds [12].

Phytoremediation, or the use of plants (specifically plant roots), to remove

contaminants and biological treatments will be addressed in Chapter 4 of this

thesis, Section 4.1.

2.3. Investigated Modes of Arsenic Remediation

Arsenic contamination can be reduced with several different remediation

methods falling under the categories described in section 2.2. In this section, an

introduction to the multitude of remediation techniques tested in Bangladesh and

West Bengal, India is followed by a review of removal strategies implemented in

the contaminated regions of Mexico. Each remediation technique is described

and evaluated with respect to cultural sensitivity, acceptability, and sustainability.

2.3.1. Bangladesh and West Bengal, India

Bangladesh and West Bengal, India solved problems associated with

access to drinking water by installing shallow tubewells in flood plain aquifers. In

solving one health problem, another was created – arsenic poisoning due to

ingestion from contaminated tubewell water. Water in the shallow aquifers is

routinely contaminated with mobilized arsenic above recommended limits, putting

millions at risk for arsenic poisoning. Many different scaled-down technologies

have been introduced to the region and evaluated for their effectiveness. These

20

methods fall under well-known arsenic removal categories outlined in section

2.2., paragraph one and include [17]:

• Oxidation

• Co-precipitation/adsorption

• Sorptive filtration

• Ion exchange

• Membranes

Oxidation Due to arsenic speciation in groundwater, many technologies take

advantage of the easier-to-remove pentavalent form of As(V) by oxidizing the

trivalent form As(III), converting it to pentavalent arsenic. This can be done using

oxygen, ozone, free chlorine, hypochlorite, permanganate, hydrogen peroxide,

and Fenton’s reagent; but the most frequently used are atmospheric oxygen,

hypochlorite, and permanganate. However, the use of atmospheric oxygen can

take weeks to convert all trivalent species to pentavalent arsenic [18]. The

chemical reactions for these three oxidation methods are as follows [17]:

H3AsO3 + ½O2 → H2AsO4- + H+ (1)

H3AsO3 + HClO → HAsO42- + 3H+ + Cl- (2)

3H3AsO3 + 2KMnO4 → 3HAsO42- +2MnO2+ +2K+ + 4H+ + H2O (3)

Processes taking advantage of oxidation are passive sedimentation, in situ

oxidation, and solar oxidation [17].

Passive sedimentation has been discussed in section 1.1.1 as a method

for turbidity reduction, but it can also apply in the reduction of arsenic by

21

oxidation. Drinking water is exposed to atmospheric oxygen during the gathering

and storing process and, as a result, this process has been studied to determine

if arsenic concentration is reduced. Fifty percent removal was obtained using

passive sedimentation of drinking water with 380-480 mg L-1 of CaCO3 for

alkalinity and 8-12 mg L-1 of iron, but most studies only showed a 25% reduction

which is not enough in most of Bangladesh and India [19].

In situ oxidation was performed under the DPHE (Department of Public

Health Engineering) - Danida Arsenic Mitigation Pilot Project where a tubewell

was aerated by the injection of aerated water into the well. As a result, the

atmospheric oxygen converts As(III) to the less mobile pentavalent form and

ferrous iron present in the aquifer is converted to ferric iron. This combination of

conversion results in a coprecipitation/adsorption process, reducing mobilized

arsenic in the well water by the following equations (surface sites are denoted

with an italicized S) [17]:

Fe(OH)3 + H3AsO4 → FeAsO4·2H2O + H2O (4)

SFeOH0 + AsO43- + 3H+ → SFeH2AsO4 + H2O (5)

SFeOH0 + AsO43- + 2H+ → SFeHAsO4

- + H2O[20] (6)

This technology reduces arsenic content by about 50% [21].

Solar oxidation takes advantage of both solar ultraviolet (UV) radiation and

atmospheric oxygen [22]. It was found that UV radiation can catalyze the

oxidation process with atmospheric oxygen, resulting in a 66% removal rate, on

average [17].

22

Co-precipitation and Adsorption Co-precipitation processes were discussed in

section 1.1.2. paragraph two as a method for reducing turbidity in drinking water,

but coprecipitation coupled with adsorption can also remove mobilized arsenic.

Seven different coprecipitation/adsorption technologies have been implemented

and evaluated in Bangladesh and India, these include:

• bucket treatment units (BTU)

• Stevens Institute Technology (SIT)

• Bangladesh Council of Scientific and Industrial Research Filter Unit

(BCSIR)

• fill and draw units

• arsenic removal units attached to tubewells

• naturally occurring iron

Different coagulants/flocculants can be employed in this process, some of

which are aluminum alum (Al2(SO4)3·18H2O, also known as aluminum sulfate),

ferric chloride (FeCl3), and ferric sulfate (Fe2(SO4)3·7H2O). The co-

precipitation/adsorption process is typical of other flocculation methods. A dose

of the flocculant is added to water, agitated for a few minutes while aggregated

flocs form, slowly stirred for a few minutes to allow for the flocs to gain in size

and begin to settle, and then let sit to allow all of the flocs to settle. Arsenic is

adsorbed onto these flocs, and, thus, removed by sedimentation. Again, for this

technology to be efficient, trivalent arsenic must first be oxidized to its charged

pentavalent form [17] but this can easily be performed using atmospheric oxygen

or the combination of oxygen and UV radiation [22]. Proposed chemical

23

reactions for the formation of and coprecipitation/adsorption of the aluminum-

arsenic complex using alum are as follows. Chemical reactions involving ferric

salts are the same as equations 4 through 6 and also require pretreatment to

oxidize As(III) to As(V) [17].

Alum dissolution:

Al2(SO4)3·18H2O → 2Al3+ + 3SO42- + 18H2O (7)

Aluminum precipitation (acidic):

2Al3+ + 6H2O → 2Al(OH)3 + 6H+ (8)

Co-precipitation:

H2AsO4- + Al(OH)3 → Al-As + Other Products (9)

The DPHE-Danida Project developed the BTU technology introduced in

Bangladesh. It requires the use of two buckets (20 L); one to perform

flocculation/coagulation and sedimentation and the other consists of a sand filter

to remove resulting contaminants. Next, 200 mg L-1 and 2 mg L-1 doses of a

chemical flocculant, alum, are added to the flocculation bucket and stirred rapidly

for one to two minutes. Then, the contents are allowed to settle. A valve in a

hose connected just above the bottom of the bucket is then opened, allowing the

supernatant to flow into the second bucket (sand filter) [17]. Thousands of these

units were distributed in Bangladesh and a rapid preliminary study by BAMWSP

(Bangladesh Arsenic Mitigation Water Supply Project, BDFID (British Department

for International Development) and WaterAid in 2001, reported mixed results.

They were found to be inefficient in reducing arsenic content below the

Bangladesh limit of 50 µg L-1 under rural use. The inefficiencies were blamed on

24

poor mixing conditions and varying pH of water supplies [19]. The BTU

technology falls under most of the requirements for socio-cultural acceptability

discussed in the introduction to this chapter, but fails to use indigenous materials

for remediation. Specifically, the flocculant is not a material known to community

members.

The SIT configuration is analogous to the BTU setup. It also consists of

two buckets, one for mixing and flocculation, and the other as a secondary sand

filter. The difference in the SIT technology is the flocculant used, the location of

sedimentation, and the configuration of the sand filter bucket. The SIT uses iron

sulphate and calcium hypochloride as flocculants. These chemicals are mixed in

the first bucket. Then, the bucket contents are poured into the second bucket that

consists of a smaller bucket with perforations inserted on top of a sand filter.

Sedimentation takes place in this second bucket, and water is drawn from

underneath the sand filter by a hose [17]. Figure 5 shows the general

configuration of the SIT.

Figure 5: Schematic of the Stevens Institute Technology Bucket Treatment Units.

Rapid assessment of the SIT showed arsenic reduction to levels below the 50 µg

L-1 requirements in 80 – 95% of cases. However, the sand filter was found to

clog frequently due to sedimentation in the second bucket [19]. This method fails

under the requirements for cultural sensitivity for the same reasons as the BTU

method. It uses foreign chemical flocculants and requires skillful operation.

The BCSIR filter unit is similar to both the BTU and SIT methods with the

differences again in the flocculant chemicals and the sand filter treatment [17,

23]. The flocculant is a mixture of iron oxide, alum, activated charcoal and

calcium carbonate. The flocs formed settle and the entire bucket of water is

passed through a sand filter that contains iron-bearing minerals of various grain

sizes. Drawbacks of this technology are the requirement of the flocculant dose

on level of contamination [23] and the lack of dependence on indigenous

materials (the use of chemicals as a flocculant). The BCSIR claims that arsenic

contaminated drinking water can be reduced to levels below the 50 µg L-1

25

standard for waters containing up to 2.7 mg L-1 As [23]. However, the BCSIR did

not take part in the rapid assessment program [17].

The fill and draw unit initiated by DPHE-Danida Arsenic Mitigation Pilot

Project is essentially a larger version of the aforementioned methods, aimed at

community-based use instead of individual household use. Flocculation takes

place in a large (600 L) tank with a mixer of flat-blade impellers and is operated

by hand. Chemical oxidants and flocculants are added, mixed, and allowed to

settle. The resulting supernatant is withdrawn from a few inches above the

sludge line near the bottom of the tank and passed through a sand filter, finally

collected at the end for drinking purposes. These units performed better

because the mixing and flocculation are better controlled, resulting in higher

removal efficiencies. These units are still serving communities and some

educational institutions in the form illustrated in Figure 6 [17].

Figure 6: Schematic of the DPHE-Danida Arsenic Mitigation Pilot Project Fill and

Draw Units.

26

Arsenic removal units attached to tubewells have been implemented in

West Bengal, India and are designed and built to be attached directly to a

tubewell outlet. This employs the use of sodium hypochlorite and alum for

coagulation, followed by sedimentation and subsequent filtration through an

upflow filter unit. This technology is designed to be used for an entire village and

has been shown to remove 90% of arsenic from the contaminated source with an

initial concentration of 0.3 mg L-1 [17]. A schematic of this design is presented in

Figure 7.

Figure 7: Schematic of Arsenic Removal Units Attached to a Tubewell in West

Bengal, India.

It was found that most drinking water sources with low amounts of iron

precipitates (<1 mg L-1) also had low arsenic values (<50 µg L-1), and those with

iron precipitates between 1 and 5 mg L-1 only satisfied the 50 µg L-1 limit 50% of

the time, and those with >5 mg L-1 only satisfied the limit 25% of the time. It has

also been found that only aeration and subsequent sedimentation of drinking

water with high iron content suitably removes arsenic. From this data and data

showing that Iron Removal Plants (IRP) which use the same methods of aeration

27

28

and sedimentation with subsequent filtration, also removed arsenic without any

added chemicals, medium scale IRPs were installed in district towns. These

IRPs suitably remove arsenic with the only disadvantage of the technology’s high

use being treated water for backwashing the filters [17].

Sorptive Filtration Sorptive filtration requires the use of a sorptive media, and

all proposed media have one universal drawback: saturation, meaning the media

is spent and can no longer remove arsenic without regeneration [17]. The

different media types employed fall under two broad categories: foreign (usually

chemical-based), and indigenous (usually natural-based). Some sorptive media

investigated for arsenic removal are as follows [17]:

Foreign:

• activated alumina

• activated carbon

• iron coated sand

• iron and manganese coated sand

• kaolinite clay

• hydrated ferric oxide

• activated bauxite

• titanium oxide

• silicon oxide

Indigenous:

• oxidized iron-rich soil

29

• clay minerals

• iron ore

• iron scrap

• iron filings

• processed cellulose

Both the foreign material-based filters and indigenous filters are generally

effective at removing arsenic but must be frequently regenerated and most suffer

the effects of fouling [17]. The use of indigenous materials is well advised in

devising a sustainable arsenic removal technology, but these technologies suffer

the same two drawbacks as the foreign materials: labor-intensive regeneration

and problems with fouling.

Ion Exchange This process is similar to sorptive filtration except that the

sorptive media is replaced with a synthetic ion exchange resin designed for

optimized removal. This technology also requires regeneration when the resin is

spent. An example of the chemical process is outlined below (where italicized R

denotes resin).

Arsenic Removal

2R-Cl + HAsO42- → R2HAsO4 + 2Cl- (10)

Regeneration

R2HAsO4 + 2N+ +2Cl- → 2R-Cl + HAsO42- + 2Na+[17] (11)

The ion exchange process efficiency, like most others, depends on an oxidation

pretreatment step [17]. The use of a foreign ion exchange resin in community

30

households does not fit the requirement that materials be familiar to community

members. Also, regeneration with other chemicals is labor-intensive and adds

another step with a foreign material. Although this technology is promising for

arsenic removal, it is not an ideal technology from the sustainability standpoint.

Membranes The membrane technologies proposed and tested for use in

Bangladesh and India are similar to and fall under the same category as the

membrane technologies discussed previously in section 2.2. The MRT-1000 and

Reid System Ltd. technologies relied upon reverse osmosis on the household

level to remove arsenic and found that both effectively removed arsenic, but the

technologies are too costly for wide implementation [17].

J.I. Oh et al., 2000, at the University of Tokyo, developed one interesting

technology [24]. It employed the use of a bicycle pump to feed contaminated

drinking water at low pressure to a filtration system. This technology was

developed for use in regions without access to electricity. Nanofiltration and

reverse osmosis were both tested, and the reverse osmosis system removed the

most arsenic at a pressure of 4 MPa. However, the nanofiltration unit was highly

efficient at removing arsenate (As(V)), showing a 99% removal, but less efficient

at removing arsenite (As(III)), with 55% removal. Oxidative pretreatment to

convert arsenite to arsenate will help the total arsenic removal efficiency [24].

The reverse osmosis system adequately removes arsenic to below the 50 µg L-1

standard, but the technology, like the other reverse osmosis method, is costly

31

and is not comprised of indigenous materials, leading to the conclusion that it,

too, is unsuitable for sustainability cultural sensitivity.

In summary, none of the techniques for arsenic removal tested in

Bangladesh or India fit the requirements for sustainability with respect to cultural

sensitivity laid forth by Shaban et al., 2005, that provide the boundaries for our

project. The requirements that technologies developed for implementation in

low-income, rural communities should be simple, easy to produce, inexpensive,

employ indigenous or easily accessible materials, and have a rural focus [11],

are not considered in existing technologies. The coprecipitation/adsorption

technologies such as the BTUs and Sits are easy to produce, inexpensive, and

have a rural focus, but they do not employ indigenous or easily accessible

materials due to their dependence on chemical flocculants. Sorptive filtration

units also tend to employ chemicals for the regeneration of sorptive medias, as

does ion exchange technologies and both produce waste materials. Also, neither

sorptive filtration nor ion exchange has a rural focus, both relying on labor-

intensive regeneration processes. The nanofiltration and reverse osmosis

membrane technologies are promising with regards to arsenic removal but fail

when held up to the standards of sustainability due to their high capital and

operation costs.

The technology with the most room for improvement with respect to

sustainability is the coprecipitation/adsorption processes like the BTUs and SITs.

If their dependence upon chemical flocculants can be alleviated, they will fit well

within the guidelines for sustainable arsenic removal technologies in low-income,

32

indigenous communities. This project seeks to develop a similar filtration unit

that employs flocculation, precipitation, and filtration but uses only indigenous,

easily accessible materials.

2.3.2. Mexico

Due to the minimal success of in-home filters and other remedies in

Bangladesh and West Bengal, India, there is a growing demand for natural

flocculants that will perform at efficiencies comparable to existing chemical

flocculants and simultaneously remove suspended solids, as well as heavy

metals [25]. To ensure a sustainable impact, the natural technology must also be

socially appropriate, producing a minimized effect on the lives of affected

individuals while simultaneously increasing their quality of life. It is this need that

motivated the initiation of a project to investigate the scientific basis, feasibility,

and product development of a natural filter for use in Mexican communities

experiencing problems with contaminated water supplies.

Mexico’s geographic, social, and economical characteristics make it the

ideal location for this water treatment project. Severe heavy metal contamination

in water supplies has created a desperate need for a treatment solution and the

current economic conditions provide a comparable situation with other areas

suffering contamination: Bangladesh, China, and India. Also, the Mexican

people are extremely familiar with our chosen flocculant source, the nopal cactus

(commonly called “prickly pear’), due to its amazing abundance in the arid

33

climates of the country. The need for a functional, inexpensive, and accessible

flocculant source is also dire due to a lack of funding for the construction and

implementation of beneficial water treatment facilities in affected Mexican

communities.

Many of the aforementioned arsenic removal technologies have been

investigated for use in affected communities in Mexico. Those investigated fall

into four separate categories: adsorption on iron-based adsorbents, adsorption

on other adsorbents, precipitation/coprecipitation, and emerging technologies.

All of the technologies described in this section have been studied for use in

other countries and have found varying success. As a result of knowledge

gained from previous implementation, most of the Mexican trials were

scientifically successful. However, their social applicability varies and are

described below.

Iron-based Adsorption Hematite and natural minerals present in Mexican

aquifers have been tested for their efficiency in adsorbing mobilized arsenic.

Simeonova, 2000, selected natural Hematite for an in situ pilot study of removal

from an underground water source in Mexico [26]. Water obtained from the

treated water source was consistently below the Mexican drinking water standard

of 50 μg L-1 [26]. Carrillo and Drever, 1998, found similar results in their study of

the possibility of using natural aquifer minerals for in situ removal. They found

that removal was, at maximum, 80% when the natural minerals contained from

10-12% Fe. It was determined that the partial removal was based on selectivity

34

for arsenate over the difficult-to-remove arsenite. Quartz, feldspar, calcite,

chlorite, illite, and magnetite/hematite were all present in their adsorbent sample

[27].

The social acceptability of these iron-based adsorption methods is high

based on the use of natural, indigenous materials. However, there is a lack of a

rural focus to these methodologies. There is a limited ability for residents in rural

communities to inject adsorbents into aquifers for in situ treatment. Also, due to

the possible presence of a governmental distrust amongst community members,

the prospect of injecting anything into an aquifer may cause suspicion.

Adsorption The adsorption techniques studied include the use of natural,

indigenous non-ferric minerals and natural zeolites. A naturally occurring, clay-

rich limestone material called Soyatal Formation was analyzed for its ability to

adsorb arsenic and was found to be an outstanding performer. Contaminated

water samples of 600 μg L-1 were cleaned to below 30 μg L-1 As. It was found

that a weight ratio of 1:10 rock-to-water is the proper dosage to reduce arsenic

levels from 500 μg L-1 to below 30 μg L-1 [28]. It would follow that lower doses

would be required for contaminated water with lower levels of arsenic. The

Soyatol Formation owes its abilities to its composition; it contains kaolinite and

illite, which are both known arsenic adsorbers [28].

Natural zeolites of the clinoptilolite variety formed in Mexico were also

investigated for their adsorption efficiency and were found to reduce

35

contaminated water with 200 μg L-1 As to 10 μg L-1, the WHO recommended

limit. The presence of anions and cations did not effect the arsenic removal [29].

Both of these natural minerals are excellent arsenic absorbers and also fit

the requirements for social acceptability. If implemented in such a way that

individual households could have control of their water treatment, this method

would also have a rural focus. The limiting factor with these methods is

sustainability. While both minerals are formed in Mexico, mining of the minerals

could affect the cost of such a treatment.

Precipitation/Coprecipitation Combination treatments consisting of alum and

a polymeric anion flocculant (PAF), as well as ferric sulfate flocculation have

been determined to be efficient modes of remediation. The combination

flocculant removed 99% of arsenic at an NaOH-adjusted pH of 7.1 and the PAF

played no part in As removal [30]. The ferric sulfate removal process

investigated consisted of a tank outfitted with a manual agitator. Ferric sulfate

salts were added by individual households (10 families) and the tanks were

agitated and left to settle for three hours. The clean water was then decanted.

Removal was total in seven of the ten systems and >93% in the other three [31].

Both flocculation methods are scientifically solid, but socially

unacceptable. The use of unindigenous chemicals to treat contaminated water is

a source of instability with respect to sustainability due to distrust in unfamiliar

materials. Also, the use of chemicals adversely affects the cost of the treatment

process.

36

Emerging Technologies Electro-remediation was discussed in section 2.2 of

this thesis. A form of electro-remediation, electrocoagulation, was performed in

the Comarca Lagunera region of Mexico for treating contaminated well water.

Electrocoagulation is a technique unlike those discussed above. It does not

require chemicals, nor does it require labor-intensive and cost sensitive

regeneration, as do most filters and ion exchange technologies. Results of the

pilot study show removal of more than 99% of arsenic due to the mutualistic

effect of the presence of magnetite particles and amorphous iron oxyhydroxides

[32]. Electrodialysis was also investigated by Clifford and Lin who found it most

effective at removing arsenic in waters with low levels of arsenite (73% removal).

Elevated arsenite concentration reduced removal to only 28% [33].

Phytoremediation was also investigated in Mexico, specifically in the mine

sites and hot springs of Chihuahua. An investigation into arsenic-bearing plants

of the region identified a native plant, Eleocharis sp. with great potential for

arsenic removal [34].

Emerging technologies are exciting due to their ability to be both

scientifically and socially acceptable. Electro-remediation does not have a rural

focus; however, due to the fact that many rural families in under-developed

countries do not have access to electricity. Phytoremediation, however, is an

ideal technology from the social acceptability and sustainability standpoints.

Plants are easily reproduced and are an indigenous, natural resource trusted by

communities. The technique outlined in this thesis can potentially be considered

37

as a combination of the scientific acceptability of precipitation/coprecipitation with

the social and sustainability sensibilities of phytoremediation.

38

Chapter Three

Water Contamination in Four Mexican Communities

Just as arsenic contaminated drinking water is quickly becoming a globally

recognized problem in areas such as Bangladesh and India where millions of

residents are potentially exposed to arsenic contamination [17], the same

problem is also being uncovered in low-income, indigenous communities in rural

Mexico. Razo, et al., 2004, studied the Villa de la Paz-Matehuala region to

determine the effect of mining in the area on sands, sediments, and surface

waters, and found arsenic levels in Carbonera and Cerrito Blanco well systems to

be greater than 6,000 µg L-1, or more than 120 times the Mexican water quality

guidelines at that time (<50 µg L-1) [35]. Sediment samples from the wells were

not studied, but sediments from nearby channels were found to be as much as

20 times the Mexican guidelines [35]. Another Mexican region similar to the Villa

de la Paz-Matehuala area is the mining district of Zimapán. Previously reported

figures for groundwater arsenic contamination in Zimapán show levels greater

than 300 µg L-1 [36]. Mejia et al. [37] studied urine samples from children in Villa

de la Paz and found arsenic levels greater than 100 μg g-1 in 28% of children

tested, proving a need for a technological solution.

The first action taken under the project was a survey of drinking water

supplies of Mexican towns chosen because of known or suspected drinking

water contamination, due to their proximity to either geologic or industrial sources

of arsenic contamination. University of South Florida (USF) geologists examined

water samples from four different communities, Region Lagunera, Zimapán,

Hierve el Agua, and Temamatla, illustrated in Figure 8, for arsenic concentration

using hydride generation-atomic fluorescence spectrometry. They also noted

suspended solid presence in the samples. The results are summarized in Table

3 along with suspected sources of arsenic contamination. The test community

for this project was chosen based on the presence of arsenic contamination

above WHO recommended guidelines and the presence of suspended solids.

Figure 8: Mexican Communities Surveyed for Contaminated Water.

39

40

Table 3: Contamination in Four Mexican Communities.

Location As

(μg L-1)Suspended

Solids Contamination

Source

Hierve el Agua >518 None Geologic Zimapán > 221 None Industrial

Region Lagunera >563 None Industrial Temamatla > 29 Present Geologic

Drinking water standard < 50

3.1. Zimapán

USF engineers and geologists found an average arsenic concentration in

drinking water samples taken from Zimapán, Mexico to be greater than 221 μg L-

1, more than four times the Mexican standard and more than 22 times the

recommended WHO guidelines.

Zimapán is mainly a mining district where Ag, Zn, and Pb ores are

processed. Also, smelters operated in the district until the 1940’s. Wastes from

these industries have collected in areas along the Toliman River. It is these

industrial sources, as well as arsenic-bearing minerals, contaminating the

drinking water of Zimapán[38, 39]. Arsenic was initially found in shallow wells of

the Zimapán basin in 1992 as part of a study detecting cholera. Residents of this

region obtain drinking water from these shallow wells due to the lack of

groundwater supplies in the semi-arid landscape [39].

While arsenic contamination in this region is well above arsenic standard

guidelines, the residents of Zimapán were not experiencing contamination due to

suspended solids, so this study did not adopt Zimapán as a test community.

41

3.2. Region Lagunera

Arsenic contamination in Region Lagunera is attributed mainly to mining

sources, and the population drinking contaminated water show As-related skin

disorders [40]. Pineda-Zavaleta et al studied children from three primary schools

in the region and found that 92% had urinary arsenic levels above 50 μg L-1,

indicating widespread exposure [41]. USF researchers found data to corroborate

previous studies: arsenic levels greater than 550 μg L-1. However, once again,

this region did not have contamination due to suspended solids so it was not

adopted as a test community.

3.3. Hierve el Agua

Hierve el Agua is a region well known for its mineral-rich waters. There

are canals and terraces built in Oaxaca, Mexico of unknown purpose but the

waters’ riches lead prognosticators to two separate hypotheses: either the region

was used agricultural purposes or for salt production [42]. If either of these

hypotheses is true, the creators of the irrigation features could not have known

the mineral-laden waters bore high levels of arsenic.

We found As levels greater than 500 μg L-1 in Hierve el Agua, mainly due

to geologic sources. The name “Hierve el Agua” translates to “Boiling Water”

and is an appropriate moniker for the region, which owes its popularity to the

prevalence of hot springs. Unfortunately, the belief that natural spring water from

hot springs is healthier than piped water leads many to drink copious amounts of

the arsenic-laden “health” water. Mothers even lead small children to sip from

42

the springs. Due to the staunch belief that these waters are beneficial and the

absence of a problem with suspended solids, Hierve el Agua was not considered

as a test community.

3.4. Temamatla

Temamatla was the community chosen for study due to its dual

contamination of arsenic and suspended solids from volcanic sources and a

suspected collapsed well, respectively. Temamatla lies 25 miles southeast of

Mexico City, providing fairly easy travel to the study site by collaborators in

Mexico City and their Tampa counterparts. Most community members obtain

their drinking water from a centralized well due to limited water resources. City

workers deliver water to households on a regular basis where it is stored in 55

gallon water barrels and used for all of the households’ water needs (Figure 9).

Figure 9: Typical Household Water Storage and Usage Area for Low-income

Families in Temamatla.

3.5. Socio-Cultural Impact Assessment in Temamatla

43

USF Anthropologist, Dr. Davis-Salazar, directed the second step crucial

to our success: socio-cultural impact assessment. This is a necessary

component of this project because part of the motivation for this project is the use

of a locally available material, namely the nopal cactus with which most rural

Mexican communities are intimately familiar. We will create an inexpensive,

straightforward process with this material that local communities will be able to

use, and will want to use. However, in developing countries non-locally designed

44

water systems have had minor success in terms of performance and

sustainability due to limited community participation, and, more specifically, a

failure to integrate local knowledge, customs, and beliefs in system design and

implementation, particularly in rural areas of Latin America. In other parts of the

world, most notably Bangladesh, arsenic mitigation projects, specifically, have

identified important social and cultural factors that affect the degree of success of

such projects. These factors include the value placed on water quality by the

local community, the community’s level of knowledge concerning the health

consequences of arsenic-contaminated water, the degree of compatibility

between the organizational requirements of the water technology and the social

and political structures of the local community, and gender and age-based

differences in household water use and exposure to arsenic-contaminated water.

Anthropology, defined by its holistic approach to the study of the human

experience, is in a unique position to integrate local knowledge and experience

with empirical data to develop socially informed and culturally sensitive water

supply and treatment programs.

In Temamatla, the site of our pilot study, our water tests indicate arsenic

levels above normal. Residents, however, remain very concerned about their

water quality and, therefore, are very receptive to our efforts. Interestingly, a

comment made by the mayor of the town indicates that any remediation efforts in

Temamatla should be readily apparent - that is, visible to the local residents

because they will want “proof” that action has been taken to solve the problem.

This indicates that the water treatment process we design for Temamatla must

45

be somewhat physically conspicuous. USF anthropologists determined that

Temamatla citizens preferred a domestic filter for use by individual households

out of convenience due to existing drinking water infrastructure and a certain

amount of distrust of community officials. It was also determined that a filter

based on a Mexican cactus that grows abundantly in the community and across

the country would be more readily accepted than a chemical-based filter design.

We were able to interview the locals and speak with the mayor of the city. We

obtained very positive responses to our project because there is a collective

awareness about water quality. Additionally, the people responded exceptionally

well to the project socially because we explained that we would be utilizing the

nopal plant to remediate their problem. They know the plant; they use it regularly

in their diet and know its availability in the region. As a final phase of the

planning grant, we will design a filter-kit for the main well. This is something that

is feasible since the line is centralized and it is already maintained by two state

workers from 5am to 10pm daily. Economically, this is a better solution than

implementing the filter-kits domestically since we will have to train only the two

workers and because the water flow is relatively small (20 L s-1). We expect that

each community for this project will design specific solutions according to their

needs.

3.6. Implications for This Project

The results of the socio-cultural assessment provided more design

boundaries for this project. In summary, a culturally accepted water treatment

46

method would be one in an in-home filter form with technology based on native

Mexican cactus. Also, a centralized treatment system placed at the drinking

water source would be an acceptable, economic application with respect to the

culture of Temamatla. Most importantly, to maintain community trust and interest

in the project, visibility is key.

47

Chapter Four

The Mexican Cactus as a Natural Technology for Water Treatment

4.1. Current Options: Natural Technologies

USEPA-recognized natural technologies for water treatment are all

considered emerging technologies by the agency. They acknowledge two very

different biological treatment options: phytoremediation and microbiological

removal processes. Phytoremediation exploits some plants’ natural ability to

remove heavy metals through root uptake, and microbial processes use

microbes that can aid in the precipitation/coprecipitation of arsenic either by

producing conditions supporting precipitation or by converting arsenic to species

that are easier to remove [12].

Phytoremediation is a viable technology for small-scale water sources

serving communities of less than 10,000 people. Elless et al., 2005,

demonstrated this technology in New Mexico, employing Pteris vittata ferns with

root systems submerged in contaminated water. `Throughputs as high as 1944 L

day-1 were treated and resulting arsenic levels were lower than the detection limit

of 2 μg L-1. However, the initial contamination never exceeded 14 μg L-1 [43].

This technology would have to be evaluated further in order to treat sources with

higher levels of arsenic contamination.

48

Other plants investigated for use in phytoremediation are poplar,

cottonwood, sunflower, Indian mustard, and corn [12]. This is a technology

highly dependent upon agricultural factors such as temperature, sunlight,

seasons, etc. These variables can be controlled by treating the water in a

greenhouse environment with a controlled environment [12].

Microbiological removal processes exploit sulfate-reducing and arsenic-

reducing bacteria to create improved conditions for precipitation/coprecipitation.

A simple schematic of a typical biological treatment process is shown in Figure

10 [12]. Katsoyiannis et al., 2004, used bacteria native to iron-rich groundwaters

in an upflow packed-media filter to remove iron and arsenic from drinking water

[44]. The two most prevalent bacteria were Gallionella ferruginea and Leptothrix

ochracea. The two most important factors in their biological treatment were

redox potential and dissolved oxygen concentration. A redox potential of 320 mV

was optimal for the removal of As, specifically in the trivalent form. Residual As

values were always below 5 μg L-1 at this redox potential. This is due to

oxidation of As(III) to its pentavalent form at this redox potential [44].

Figure 10: Schematic of a Typical Microbiological Arsenic Treatment Unit.

The successes of phytoremediation and microbiological treatment for

arsenic removal are promising, giving weight to both of these emerging fields.

There are currently no natural flocculants used for the removal of arsenic to the

best of our knowledge.

4.2. Proposed Source of Natural Flocculant: Opuntia ficus-indica

The genus Opuntia is the largest under the Cactaceae family. Varieties of

Opuntia can be found from Western Canada south to the tip of South America.

The Opuntia species chosen as a flocculant source for this project, Opuntia ficus

indica, also known as nopal or prickly pear, is commonly found and cultivated in

Mexico where it grows in tree-like proportions (Figure 11). The nopal cactus was

49

chosen as a flocculant source based on its ubiquity in Mexico and due to the

Mexican people’s familiarity with the nontoxic cactus. There is also previous

empirical knowledge of the nopal being used since ancient times in Latin America

to reduce turbidity and hardness in natural spring waters [45].

Figure 11: An Example of Opuntia Growing as a Tree in Mexico.

4.2.1. Current Uses

Opuntia ficus-indica is widely used for its nutritional value. It is used as a

fruit crop and a vegetable crop for human consumption [46, 47], and as a forage

crop for livestock in drought conditions [46]. The fruit of the Opuntia is commonly

referred to as tunas, their Spanish name [48]. Typically, the fruit is dried for use

during the winter, but sometimes a sauce is made from boiled, unripe fruits.

They are also used for their skins, (food coloring), their syrup (tuna honey),

fermented and nonfermented beverages, and in the dried form as tuna cheese

[49]. The seeds of the tuna have also been ground and used as a meal by some

American Indians. The fruits have been shown to be a source of sugars (15%

50

51

sugars and 85% water) and even a source of small amounts of Vitamin C. They

typically have a pH around 6.5 and are rich in calcium and phosphorous [46].

The advantage of using Opuntia as a fruit crop is the ability to grow cactus in

otherwise unfertile, rocky soil. Crop concentrations of 20,000 kg of fruit hectare-1

have been produced, which equates to about 2,800 kg of sugar [48].

The use of Opuntia as a vegetable crop is less popular. Typically, only the

young joints of the cactus (nopalitos) are used as a vegetable in Hispanic

households [50]. They are typically cooked as a green vegetable or marinated

as part of a salad [46]. The cactus skin and thorns can be easily removed,

leaving the edible insides of the cactus pad [51]. Opuntia pads have been shown

to be made up of 87% water, 1% protein, 0.1% fat, 1.3% ash, 1.1% crude fiber,

and 5.4% carbohydrates [50].

In drought conditions, when grasses and other forage crops are no longer

edible, the Opuntia cactus remains green and is used as an emergency feed

crop for ranging livestock in both the southwestern United States and Mexico

[51]. The spines are burned off, soaked in water, or washed with soda to

eliminate their harmful effects on the livestock. Sheep have lived for up to 8

months eating entirely Opuntia [46].

Opuntia is not used exclusively as a food source. They are popular as

ornamental and hedge plants and the stem of the cactus is used in producing

decorative elements [46].

52

4.3. The Mucilage of Opuntia ficus-indica

The mucilage of Opuntia ficus-indica is a thick, gummy substance and is

what provides the cacti’s natural ability to store large amounts of water. When in

water, the mucilage swells, producing unique surface-active properties seen in

many natural gums, giving the mucilage a suspected ability to precipitate

particles and ions from aqueous solutions. The mucilage is extracted from the

pads of the cactus. Diced nopal cladodes have been used for centuries in Latin

America as a primitive technology for the rapid flocculation of turbid natural

spring waters, but a scientific baseline has never been provided for this observed

phenomenon [45].

4.3.1. Chemical Composition

The mucilage of Opuntia ficus-indica is composed of 55 sugar residues

including arabinose, rhamnose, galactose, and xylose, and some, specifically

Burbank’s cv Spineless, show fractions of glucans and glycoproteins [52]. The

mucilage of Opuntia ficus-indica has been a source of some confusion amongst

investigators [45].

The molecular weight of the mucilage has been reported as different

values, probably also due to differences in extraction techniques and the

possibility of contaminants [45]. In 1981, Trachtenberg and Mayer reported a

molecular weight of 4.3 · 106 g mol-1 [53], but a study by Cárdenas et al. in 1997,

reported a value of 3 · 106 g mol-1 [54], and in 2000, Medina-Torres et al.

reported 2.3 · 106 g mol-1 [53-55].

53

In 2001, Madjoub et al isolated two separate mucilage fractions, calling

one the “high weight sample” (HWS) with a molecular weight of 13 · 106 g mol-1

and the other the “low weight sample” (LWS) with a molecular weight of 3.9 · 103

g mol-1 [56]. The HWS was determined to make up about 10% of the total

mucilage content and was devoid of proteins. It contained about 20% charged

sugar [56], leading to the possibility of its potential to interact with divalent cations

[45]. The sugars detected in the HWS were the same as reported previously in

the literature and in this thesis.

Madjoub’s LWS was determined to be composed mostly (~80%) of protein

with a nitrogen composition of 2.2% [56], helping to confirm the presence of

glycoproteins in mucilage. Table 4 summarizes research results on the chemical

constituents of Opuntia mucilage.

Table 4: Differences in Detected Mucilage Properties: Molecular Weight and Sugar Content.

Author

MW (g mol-1) G

alac

tose

Rha

mno

se

Ara

bino

se

Xyl

ose

Uro

nic

acid

Gal

acto

se/

Ara

bino

se

Cárdenas et al (1997) [54] 3 × 106 + + + +

Trachtenberg & Mayer (1282) [57] 1.56 × 106

McGarvie and Parolis (1981) [58] + + + + +

McGarvie and Parolis (1981) [59] + + + 1.5/3

Trachtenberg & Mayer (1981) [53] 4.3 × 106 + + + + + 4.9/3

McGarvie and Parolis (1979) [60] + + + + + 1.3/3

Paulsen and Lund (1979) [61] + + + + + 2.3/3

Saag et al. (1975) [62] + + + + + 3.5/3

McGarvie and Parolis studied the chemical structure of the mucilage and

proposed the structure represented in Figure 12, with R indicating the presence

of different arabinose and xylose forms, D-Gal indicating D-galacturonic acid, Gal

indicating galactose, and Rha indicating Rhamnose [45, 58, 59].

Figure 12: McGarvie and Parolis's Proposed Mucilage Structure, Taken from

Sáenz, 2004.

4.3.2. Extraction Techniques

The mucilage was extracted prior to the inception of the portion of the

project described by this thesis. What follows is an overview of the techniques

used to extract the mucilage used in the flocculation and arsenic removal project.

The cactus pads used for the gelling extract (GE) and the nongelling extract (NE)

were cut from plants obtained from Living Stones Nursery, Tucson, Arizona and

pads used for the combined extract (CE) were obtained from Blue Diamond

Nursery, Las Vegas, Nevada. They were then potted and allowed to acclimate in

direct sunlight before the mucilage was extracted.

54

55

In total, three types of mucilage were extracted. A modified method

detailed by Goycoolea and Cárdenas was used to obtain GE and NE [63], and

CE, consisting of GE & NE, was obtained using the method outlined by Medina-

Torres et al. [55]. All mucilage types extracted were stored dry and at room

temperature.

Gelling and Nongelling Extracts The Goycoolea and Cárdenas method was

used as a guideline in extracting the GE and NE used in the flocculation and

arsenic experiments. However, changes were made in order to maximize

mucilage extraction. The actual procedure implemented is outlined in

Figure 13 with boxes highlighting the modified steps.

Figure 13: Modified Goycoolea and Cárdenas Extraction Method.

Combined Extract The Medina-Torres et al., 2000, method [55] is a modified

version of a method used by McGarvie and Parolis in 1979 [55, 60]. Two nopal

pads were macerated in a blender and the resulting solids and liquid supernatant

were separated in a centrifuge at 4000 rpm. The resulting supernatant was

collected and mucilage was precipitated with a 1:2 ratio of pulp to acetone. The

acetone was decanted and the precipitate was washed with a 1:1 volume ratio of

precipitate to isopropanol. The resulting precipitate was air dried on a watch

glass.

56

57

4.3.3. Current Applications

Opuntia mucilage has been extracted and evaluated for uses including dietary

fiber [64], medicinal [65-69], digestive [70, 71], lime mortar additive [72], and

emulsifying agents [73]. The Opuntia is used as a food source by many Latin

Americans and the mucilage component of Opuntia contributes to the dietary

fiber component of the cactus [64]. The mucilage has also been investigated for

its use in controlling blood glucose levels in diabetics and cholesterol in guinea

pigs fed a high-cholesterol diet. It significantly reduced both blood glucose and

cholesterol levels [66-68, 74]. It has also been studied for its wound-healing

abilities and was found to significantly effect healing in rats when administered

topically [75].

Other non-medical uses of Opuntia mucilage have been investigated. In

Mexico, nopal juice is sometimes added to lime mortar to reduce cracking and

water penetration. However, in investigating nopal mucilage’s role in the strength

of the mortar, Cárdenas et al., found that, while it may decrease water

penetration and cracking, it also reduces the mechanical strength of the lime

mortar [72]. The mucilage has also been suggested for use in food industries

due to its efficiency in stabilizing oil-water emulsions [73].

58

Chapter Five

Physical and Chemical Analytical Methods

5.1. Mucilage Characterization: Raman Spectroscopy

Raman Spectroscopy (RS) is adept at determining functionalization of

chemical structures, especially those of organic compounds, from their

vibrational spectra. Samples analyzed with RS can exist in either the solid,

liquid, or gas states [76]. The samples of GE, NE, and CE analyzed were in the

solid phase (powder form), a condition that RS is particularly suited for since

conventional Infrared Spectroscopy (IR) provides water band interference [76].

The mucilage samples were loaded in a capillary tube, inserted in the Raman

Spectrometer, and their vibrational spectra were analyzed. The system was

purged with nitrogen to reduce interference from ambient contaminants.

5.2. Turbidity

5.2.1. Cylinder Tests

The abilities of the three mucilages (GE, NE, and CE) and aluminum sulfate to

settle suspended solids were tested with standard cylinder tests [77-86]. The

tests were performed with 50 g L-1 concentrations of kaolin in 100 mL graduated

cylinders (control). They were treated with varying doses of mucilage extract and

aluminum sulfate, and the fall of solid/liquid interface height with respect to time

59

was recorded. High concentrations of kaolin were chosen since they mimic mud

conditions and make the interface visible.

5.2.2. Jar Tests

The residual turbidity of the resulting supernatant after the suspended

solids have been settled is another benchmark with which to measure the

flocculation effectiveness of the three mucilages (GE, NE, and CE). Residual

turbidity tests were carried out according to standard jar test procedures [77, 84,

87-96]. They were performed with 0.5 g L-1 kaolin suspensions in a standard jar

test apparatus (ECE MLM4, ECE Engineering, Canada) consisting of four

identical 500 mL compartments.

5.2.3. Light Scattering

A turbidimeter (Micro 100, HF Scientific, North Andover, Massachusetts) was

used to measure the turbidity of jar test supernatant in Nephelometer Turbidity

Units (NTU), the accepted unit of turbidity [97]. A sodium lamp was utilized.

Indexed cuvettes were filled with supernatant and inserted in the optical well.

The highest measurement was recorded as the turbidity of the supernatant.

5.3. Arsenic Removal

5.3.1. Hydride Generation – Atomic Fluorescence Spectroscopy

Arsenic concentrations for the single-dose methods were determined by

hydride generation-atomic fluorescence spectrometry (HG-AFS) in the Center for

Water and Environmental Analysis at the University of South Florida. A

60

PSAnalytical 10.055 Millennium Excalibur instrument was used to determine the

total arsenic content of treated samples. Then, 10 mL of each 20 mL sample

was added to 15 mL of concentrated hydrochloric acid, used in HG-AFS in order

to produce excess H+, and 1 mL of saturated potassium iodide to convert arsenic

species to arsenite for analysis. Then, 24 mL of deionized water were added to

make the final volume 50 mL [98]. Tetraborohydride is then added in order to

form arsenic hydride (AsH3), which is then atomized in a hydrogen flame.

Fluorescence spectrometry is then utilized to establish the arsenic concentration

in the sample. Arsenic calibration curves are determined through the use of

standards prepared with arsenic reference solutions. HG-AFS is a particularly

useful technique due to the minimal presence of interference from matrix

interactions [99].

5.3.2. Atomic Absorption (AA) Spectroscopy

Atomic absorption spectrometry was used to analyze total arsenic content

in water samples. The graphite furnace (GF) technique was chosen for use in a

Varian Zeeman 240Z Atomic Absorption Spectrometer (AAS). The GF technique

is the most widely used and, as a result, the most well understood. In a graphite

tube atomizer, there is the combination of an atmosphere of inert gas and

reducing conditions produced by incandescent graphite that makes this

technique perfect for analyzing pure analytes. Also, GF technique provides a

longer residence time (two to three times greater than flame atomic absorption

spectroscopy), leading to less interferences [100].

61

Acidified arsenic samples (0.4% HNO3) were diluted by 5 with 5% Nitric

Acid in order to fit within the analyzable limits of the AAS (10 – 60 µg L-1 As).

Then, 1000 mg L-1 As standard was diluted to 10, 20, and 30 µg L-1 standards

and used to form the calibration curve, using the New Rational method for fitting.

Finally, 20 μl samples consisting of 15 μl of diluted As samples and 5 μl of a

Nickel Nitrate modifier were injected into the graphite furnace of the AAS. The

contents were atomized and analyzed with the concentrations taken from

absorption peak height.

62

Chapter Six

Experimental Procedures

6.1. Turbidity Experiments

6.1.1 Materials

The reagents, equipment, and instruments used in the flocculation

experiments performed are listed in Table 5 and Table 6.

Table 5: Reagents Used in Flocculation Experiments. Name Short Name Manufacturer Serial/Catalog No.

Aluminum Silicate (hydrated) Kaolin Fisher Scientific S71954 Sodium Hydroxide NaOH Acros Organics 206060010 Aluminum Sulfate Al2(SO4)3·18H2O Fisher Scientific S70495

Gelling Extract GE Nongelling Extract NE Combined Extract CE

Extracted according to procedures outlined in section 5.1, this thesis.

63

Table 6: Equipment and Instruments Used in Flocculation Experiments.

Name Manufacturer Serial/

Catalog No. Model No. Range Description Minimix

Laboratory Mixer/Jar

Test Apparatus

ECE Engineering M443 ECE MLM4

Four 500 mL sample jars,

12V DC

AccuSeries II ® Analytical

Balances

Fisher Scientific 13-265-220 Accu-124 Max: 120

grams

Readability: 0.1 mg, taring, repeatability:

0.1 mg, linearity: ±0.2

mg, Accumet 1003 pH

Meter

Fisher Scientific 1003 -6 to 20 pH Resolution:

0.1, 0.01

pH Probe Accumet 13-620-111 0 to 14 pH Accuracy:

<±0.05 pH at 25 ºC

Micro 100 Turbidimeter HF Scientific 40228/20001 Micro 100 0 to 1000

NTU

Accuracy: ± 2% reading + 0.01 NTU, 30 mL sample

size

6.1.2. Cylinder Test Procedure

The procedure was uniform throughout each cylinder test performed

according to the following step-by-step explanation.

Initially, a 50 g L-1 kaolin suspension was produced by diluting 5 g of

powdered kaolin in 100 mL of Milli-Q water in a 100 mL glass volumetric flask

fitted with a glass stopper. The volumetric flask was then stoppered and fully

inverted 10 times in order to ensure the presence of a well-mixed suspension.

The suspension was then allowed to sit for 24 hours before use.

After a 24 h period, the cylinder tests were performed. The suspension

was mixed well by inverting the flask 10 times. Then, the pH of the suspension

was adjusted to 7 by adding the required amount of NaOH. The neutral

64

suspension was then mixed again by inversion and added to a 100 mL graduated

cylinder fitted with a glass stopper. Using the appropriate micropipette and

micropipette tip, the desired dose of flocculant (either Al2(SO4)3, GE, NE, or CE)

was added. An example of the dosage scheme is outlined in Appendix A. The

cylinder was then capped and inverted 10 times to ensure the suspension and

flocculant were well mixed. The cylinder was placed on a level surface and flocs

immediately began to form and settle. The height of the visible solid/liquid

interface was then recorded with time until the flocs were fully settled1.

6.1.3. Jar Test Procedure

The procedure followed for all jar tests performed was as is detailed in this

section. There were four steps to performing the residual turbidity tests:

suspension preparation, cuvette indexing, the jar tests, and the final light

scattering measurements.

Suspension Preparation Initially, a 0.5 g L-1 kaolin suspension was produced

by diluting 0.5 g of powdered kaolin in 1 L of Milli-Q water in a 1 L glass

volumetric flask with a glass stopper. This dilution was repeated once in order to

prepare another liter of suspension. Each flask was inverted 10 times to ensure

that the suspensions were well mixed. Then, the suspensions were allowed to sit

for 24 hours before use.

1 The solid/liquid interface was measured against the tic marks on the graduated cylinder. Time was recorded exactly as the interface passed a tic mark (1 cm3). The distance between the tic marks was then measured and the measured height was calculated based on this interval.

65

Cuvette Indexing Since light scattering was employed to determine the

residual turbidity, it was imperative that turbidimeter cuvettes be indexed. To do

this, the turbidimeter cuvette compartment was capped; the turbidimeter was

turned on, and allowed to warm up for about 5 minutes. Four clean, capped

turbidimeter cuvettes were chosen and the outsides were wiped to remove

fingerprints and dust. The empty cuvette was inserted into the turbidimeter

compartment. The cuvette was rotated fractions of a turn, stopping to allow the

reading to stabilize until the lowest NTU reading was determined. Finally, this

position was marked on the cuvette cap and this procedure was repeated for the

other four cuvettes.

Jar Tests Initially, the paddle header was removed from the apparatus jars.

Then, a two-step procedure was used to fill the jars. First, one flask containing

the previously prepared kaolin suspension was inverted 10 times to resuspend

the kaolin. The stopper was removed and the flask was inverted over the jars,

quickly filling each compartment equally2. This was done again for the second

flask. Any volume difference was corrected by quickly transferring suspension

from over-filled compartments to under-filled compartments. The mixing paddle

header was replaced on the jars and mixing was started at 100 rpm. The desired

flocculant dose (GE, CE, or Al2(SO4)3) was then added to the jars. An example

of dosage schemes is presented in Appendix A. Stirring continued for 2 minutes

at 100 rpm. The speed was reduced to 20 rpm for 5 minutes. Stirring was then

2 It is imperative that the filling of the jars be performed as quickly as possible to ensure the suspension in each jar test apparatus compartment is equally mixed.

66

stopped and the flocs formed were allowed to settle for 30 minutes. Samples of

the supernatant were collected from each compartment by opening the valve set

~3 cm above the bottom of the jars and filling a turbidimeter cuvette. The

cuvettes were then inserted into the turbidimeter and aligned with the previously

marked indexed alignment. The highest measurement was then recorded as the

supernatant turbidity

6.2. Arsenic Removal Experiments

6.2.1. Materials

The reagents, equipment, and instruments used in the arsenic

experiments are listed in Table 7 and Table 8.

Table 7: Reagents Used in Arsenic Removal Experiments. Name Short Name Manufacturer Serial/Catalog No.

Arsenic (III) Solid Arsenic (III) Oxide Acros Organics R45 28 34 50/53 Arsenic (V) Solid Arsenic (V) Oxide Acros Organics R45 23/25 50/53 Arsenic Standard As2O3·18H2O Hach Company 14571-42 Sodium Hydroxide NaOH Acros Organics 106060010 Aluminum Sulfate Al2(SO4)3 Fisher Scientific S70495

Nickel Nitrate Ni(NO3)·6H2O Fisher Scientific N62-500 Gelling Extract GE

Nongelling Extract NE Combined Extract CE

Mucilage was extracted according to procedures outlined in section 5.1, this thesis.

Table 8: Equipment and Instruments Used in Arsenic Removal Experiments.

Name Manufacturer Serial/

Catalog No. Model No. Range Description

Screw-top Glass Vials

Fisher Scientific 0333921J FS60957C-4 5 mL

Screw thread with PC lined cap, made from

Type I, Class B borosilicate glass

67

Table 8: Cont’d. Polystyrene

Round Bottom Tubes

Becton Dickinson 352027 8 mL Graduated with screw

cap

Syringe Becton Dickinson 309603 4120416 5 mL

Luer-LokTM tip, latex free, single use,

disposable, 1/5mL graduation

Syringe Filter Fisher Scientific 09-719-A R4DN26317 25 mm

0.22 μm pore size Mixed Cellulose Ester

(MCE), sterile, 50/package

Centrifuge Tubes

Fisher Scientific 05-539-7 11197003 50 mL

Sterile, polypropylene, plug

seal cap

AccuSeries II ® Analytical

Balances

Fisher Scientific 13-265-220 Accu-124 Max: 120

grams

Readability: 0.1 mg, taring, repeatability:

0.1 mg, linearity: ±0.2 mg,

Accumet 1003 pH

Meter

Fisher Scientific 1003 -6 to 20

pH Resolution: 0.1, 0.01

pH Probe Accumet 13-620-111 0 to 14 pH Accuracy: <±0.05 pH at 25 ºC

Atomic Absorption

Spectrometer Varian, Inc. Zeeman

240Z 10 – 100 μg L-1

Detection limit: 10 µg L-1

6.2.2. Single Dose Method Procedure

The arsenic tests were carried out using GE due to its convincing

effectiveness as a flocculent of suspended solids. Initial tests were performed by

preparing a standard arsenic solution from solid As(III) and As(V) stock in a 50

mL centrifuge vial, removing 20 mL before sample, dosing with 0.10, 1.0, and 10

mg L-1 GE, inverting 10 times, and removing a 20 mL after sample from the top of

the vial (the air-water interface) after 1 h. The samples were examined using

hydride generation-atomic fluorescence spectrometry for total As content.

In light of the data obtained, new experiments were designed with a taller

water column (300 mL of As standard prepared from a 1000 mg L-1 stock diluted

68

to ~80 μg L-1 in a 1000 mL graduated cylinder) in order to determine more

precisely the As concentrations at the air-water interface. Three columns were

dosed with 5 mg L-1 GE and inverted 10 times. Then, 5 mL samples were taken

from the top of the column after one hour and filtered with 0.22 micron mixed

cellulose ester syringe filters, acidified with 0.4 % HNO3, and tested for total As

content using atomic absorption spectroscopy. This series of experiments was

performed at three different mucilage pHs held constant: 7, 8, and 9.

Experiments were also performed in order to elicit the arsenic distribution

in the water column. A 500 mL beaker containing a port at the bottom was

outfitted with a 2mm nylon tube at the 250 mL level so samples could be taken

from the bottom and the middle of the system. The system was dosed with 5 mg

L-1 GE and stirred for 10 s. The system was then placed on a level surface.

Samples were taken at 0.5 h intervals and examined with AAS.

Finally, an experiment was performed with concentrated arsenic (10.34

mg L-1) and a high dosage concentration of GE (187.5 mg L-1) in a 50 mL

centrifuge tube. A 20 mL sample of the arsenic solution was reserved as a

before sample and 40 mL was added to the centrifuge tube. A 15 mL dose of 0.5

g L-1 GE was added to the centrifuge tube, inverted 10 times, and a 20 mL after

sample was taken from the top. These samples were examined with HG-AFS.

6.2.3. Optimization Procedure

New arsenic tests were performed using a make-up method designed to

replace spent mucilage removed from the top of the column. A mucilage pH of 8

69

was chosen due to its apparent superior performance in creating the arsenic

concentration differential. The same 300 mL water column set-up was used with

identical As stock solution and GE dosage. The column was initially dosed with

2.5 mg L-1 GE and inverted 10 times. A 5 mL sample was taken at the air-water

interface after 0.5 h and treated the same as the previous test. The 5 mL sample

was then replaced with 5 mL of GE at a concentration of 2.5 mg L-1 at the top of

the column. This procedure was performed at 0.5 h intervals for four hours. The

samples were examined using atomic absorption spectroscopy.

Based on the performance of GE in removing As, a simple filter was

designed consisting of 400 mL of sand in a beaker containing a port level at the

bottom. The filter was initially rinsed with 50 mL of distilled water, allowing all of

the water to drain. Then, it was dosed with 50 mL of GE at 1 mg L-1, allowing the

solution to completely run through the filter and discarding the filtrate. A 50 mL

volume of a 5 mg L-1 solution prepared from As(V) solid was then poured into the

filter and collected from the bottom port. The samples were then analyzed with

Hydride Generation-Atomic Fluorescence Spectrometry.

70

Chapter Seven

Results and Discussion

Experimental results are presented and discussed in this chapter. A

presentation and discussion of the chemical composition of the mucilage is

followed by the results of the turbidity and arsenic study. An evaluation of the

cultural sensitivity of the project is then followed by an evaluation of the

interdisciplinary work involved in this study.

7.1. Comparison of Extracts: Chemical Composition

Raman IR analysis of GE, NE, and CE extracts highlighted their differences and

similarities. Curiously, the spectrum for the CE matched exactly with the NE, as

can be seen in Figure 22.

Figure 14: The Matching Spectra of CE and NE.

The real differences were found to be between GE and NE (Figure 15). The NE

spectrum shows a broad peak in the isolated OH region (3600-3200 cm-1) and

peaks in the region suggesting liberation mode of residual water molecules (~800

cm-1). These are both split in the GE spectrum, suggesting two types of O-H

stretching, isolated OH species and residual water molecules attached to the

complex structure of the mucilage with is a combination of polyethers. However,

the real differences occur in areas relating to nitrogen bonding (Figure 15). Both

show nitrile peaks between 2200 cm-1 and 2400 cm-1, but NE shows a much

stronger peak. GE shows a peak in a region generally attributed to C-NH2 bonds

(~1100 cm-1). We believe it is this to which the mucilage owes its water treating

properties.

71

Figure 15: The Spectral Differences Between GE and NE.

The structures of GE and NE/CE have similar properties of polymers that

show the same functionality. Poly(ethyl cyanoacrylate), in Figure 16, shows

similar structural composition to NE/CE, is known as a bonding agent, and has

been investigated as a colloidal carrier of drugs. Figure 16 also shows poly(ethyl

acrylamide), a polymer with similar structure to GE. It also exhibits similar

properties as GE, such as its ability to form a gel, its use as a thickening agent,

and its ability to flocculate colloidal systems [101].

Figure 16: Poly(ethyl cyanoacrylate) and Poly(ethyl acrylamide).

72

73

7.2. A Comparison of Extracts: Flocculation

7.2.1. Settling Rate

The gelling extract was found to be the best performer with respect to

suspended solids removal as determined by standard cylinder tests. It out

performed NE, CE, and Al2(SO4)3, a widely used chemical flocculant and

benchmark for this study, whose usage could cause contamination and an extra

separation step in drinking water treatment. The fall in liquid-solid interface was

recorded with time, and rates were measured from the linear decay portion of

settling. The pH was a constant value of 7 during these experiments. The GE

performed at rates 3.3 times faster than that of Al2(SO4)3 at flocculant doses of 3

mg L-1 (2.20 cm min-1 for GE versus 0.67 cm min-1 for Al2(SO4)3 in Figure 1). The

control (no flocculant dose) settled at a rate of 0.56 cm min-1. As can be seen in

Figure 18, at a GE dose of 0.01 gm L-1, the mucilage performed at a rate

equivalent to Al2(SO4)3 dosed at 300 times that concentration (3 mg L-1), proving

that the GE is a more effective flocculent than the popular Al2(SO4)3 with respect

to settling rate and requiring the use of less material to obtain the same results.

Figure 17: Flocculation Rates Comparison.

Figure 18: GE Compared to Al2(SO4)3.

74

The flocculation effectiveness of all three types of mucilage with respect to

settling rate increases when dosage concentration is increased. The effect of

dose concentration is illustrated in Figure 19.

Figure 19: The Effect of Dose on the Settling Rates of GE, CE, and NE.

The effectiveness of the flocculants in this study is directly related to the

size of the flocs formed. Larger flocs fall faster under the influence of gravity,

leading to a faster settling rate. Larger flocs require more restructuring of the

settled solids in the graduated cylinders, leading to a shorter linear settling

portion. As the large flocs pile up they begin to rearrange, leading to an earlier

removal from the linear settling scheme. Examining the data in Figure 20, it is

obvious that GE performs as a faster flocculant due to its ability to form larger

75

flocs than NE, CE, and Al2(SO4)3, as is evidenced by its relatively early departure

from the linear scheme (5 min in comparison to the control’s 21 min).

Figure 20: A Comparison Showing the Differences in the Linear Portion of

Settling. The cylinder test results suggest that the ability of GE to form a gel, much like

polyacrylamide, provides it with excellent floc-forming properties. The ability of

GE to perform at the same efficiencies of Al2(SO4)3, at doses 300 times smaller is

a testament to its attractiveness as a flocculant alternative when settling rate is a

critical variable. Adding this to the fact that it is derived from a renewable

resource and is a green technology supports GE, CE, or NE as viable flocculant

alternatives.

76

7.2.2. Residual Turbidity

Residual turbidity is a critical aspect to the evaluation of the efficiency of a

flocculant. Results of jar tests performed with GE, CE, and Al2(SO4)3 show that

while higher mucilage doses improve settling rate, they degenerate residual

turbidity (Figure 21). These results suggest that GE, CE, and NE are extremely

efficient at quickly flocculating systems, but do not completely rid the system of

suspended solids. However, as is illustrated in Figure 22, at extremely low doses

(approximately 1 μg L-1 and below), the mucilage provides residual turbidities

comparable to Al2(SO4)3.

Figure 21: Residual Turbidity of the Mucilages GE and CE.

77

Figure 22: Residual Turbidity of Al2(SO4)3, GE, and CE in a Low Dose Region.

These tests were performed with solutions of very high turbidity not

indicative of the turbidities found in Temamatla. Also, the suspended solids in

the well water were observed to be of larger particle size than the kaolin used in

this study. As a result, GE, NE, or CE would all be applicable in Temamatla.

However, in areas with high turbidities, residual turbidity can be reduced by

inexpensive secondary filtration, possibly built into the filter design that is the final

goal of the overall project.

78

7.3. Gelling Extract: Arsenic Removal Efficiency

7.3.1. Single Dose Method

The data from the initial single dose experiments (Figure 31) showed a

variety of effects. The GE mucilage was definitely transporting the As in the 30

mL water column. Different concentrations showed increases of mucilage at the

bottom of the column (0.1 and 37.5 mg L-1) while the others exhibited decreasing

arsenic concentrations. It was concluded that GE was either entrapping the As

and transporting it to the air-water interface or to the bottom of the column, as it

did with suspended solids.

Figure 23: Results of the Single Dose Arsenic Tests.

79

80

Single dose experiments with CE showed little or no removal, so this

extract was abandoned for the rest of the arsenic study. The focus shifted to

eliciting the mechanism and performance of GE in removing As.

Experiments designed to determine the arsenic concentration at the top of

the water column, when dosed at different GE pH, revealed the action of the

mucilage-As complex in the water column and exposed the optimal pH for GE As

removal efficiency. The results are illustrated in Figure 33 and Figure 34. At pH

of 7 and 9, the GE caused a minimal average increase of As at the top of the

water column. However, at a pH of 8, the top As concentration was increased by

11 µg L-1. This does not agree with the action the GE distributed in flocculating

suspended solids.

Figure 24: Single Dose Experiments to Elicit the Effect of pH on As Removal.

81

Figure 25: Average Gain in Arsenic Concentration Resulting from pH Experiment. To adequately determine the action of the GE, a tri-level experiment was

designed, the results of which are presented in Figure 35. It is important to note

that in this experiment, the samples were filtered in order to remove the entire

mucilage-As complex. As a result of this procedural difference, a decrease in

arsenic concentration represents the samples containing mucilage-As

complexes. The data suggests that GE does, in fact, transport the As to the top

of the water column. At 1.5 h, the top concentration is at 57 μg L-1, reflecting a

33% removal. After 1.5 h, the data reflects a restructuring of the As

concentration profile, probably due to an event occurring during the sampling at

1.5 h. The system experienced perturbation. However, at 3 h, the top

concentration is 63.5 μg L-1, or 26% removal.

82

Figure 26: Results of the Tri-level Arsenic Distribution Experiment.

The results of a concentrated test performed with 10.4 mg L-1 As and 65

mg L-1 GE dose seem to contradict the hypothesis that the mucilage transports

As to the top of the water column. A removal of 41% As was found at the top

with this experiment, using HG-AFS, keeping in mind that an increase in As at

the top of the column would have translated to As removal since these samples

were not filtered. It seems that at high concentrations, the mucilage-As system

reaches a critical concentration, changing conformation and actually sinks to the

bottom of the water column. This is corroborated by visual inspection in a

reproduction of this test performed in a graduated cylinder. Shiny, solid particles

can be seen entrapped in the mesh of the GE and sinking to the bottom (Figure

27). These solid particles could be As or simply small air bubbles trapped in the

83

sinking mucilage, each demonstrating the action of the mucilage at high

concentrations.

Figure 27: Solid Particles Observed in High Concentration As and GE Systems.

The results of preliminary filter tests are presented in Figure 36. This

demonstrates the ability of GE to be used in a filter form with a silica matrix. This

quick, crude experiment exhibited an As removal of 3%. The results from the

single-dose tests suggest that as much as 41% removal could be obtained if the

filter design and mucilage dosage are optimized.

7.3.2. Optimization

The optimization data in Figure 37 confirms what was found in the tri-level

experiment of Figure 35. The data shows a lag time of 1.5 h before a decrease

in As concentration. As removal of 35% was reached after 3 h, compared with

33% in the tri-level experiment. This lag time is a result of the GE-As complex

diffusing to the air-water interface. This lag time will depend on water column

height. As was seen in the tri-level experiment, perturbing the water column

84

disturbs the As concentration profile. For the optimization experiments

performed where they were shaken each time after they were dosed there was

no lag or removal exhibited due to the inability of the GE to distribute in the water

column.

Figure 28: Results of the Optimization Experiments Illustrating the Importance of

Settling Time.

7.4. Cultural Sensitivity

The delimitations of this study were laid out in section 1.5 of this thesis.

They consisted of guidelines aimed at keeping the project in the realm of cultural

sensitivity. To summarize, in order to be culturally sensitive with respect to low-

income, indigenous communities, the project must provide a technology that is

simple, easily produced, and inexpensive, employ indigenous or easily

85

86

accessible materials, and have a rural focus. The results of keeping within these

guidelines are listed below.

Simplicity The extraction techniques for GE mucilage are extensive

and difficult. However, now that the Opuntia mucilage has been identified as a

flocculant, simple extraction techniques can be explored if extraction is to be

done by communities. If the mucilage is extracted by a third party and provided

to the community members, the actual treatment techniques consisting of simple

dosing and decanting techniques are simple and universally

known.Reproducibility This technology is extremely reproducible. The GE is

derived from a renewable resource, the Opuntia ficus-indica that grows

abundantly in arid and semi-arid regions. The project has at no point departed

from the Opuntia cactus as a flocculant source, for the very reason that it is a

renewable resource.

Cost Expensive treatment techniques have never been introduced into

this study. The most cost-intensive step of the procedure exists in extraction.

However, it remains to be determined if macerated Opuntia cladodes can be

used for As removal and to what extent. If that were the case, no expensive

extraction step would be required.

Materials All materials employed in this proposed technology are

familiar to community members in our target community and any other

community in an arid or semi-arid region.

Rural Focus The focus of this study has always been the community

members of the rural town of Temamatla, Mexico. Using GE for water treatment

87

is an easy method not requiring any hard labor or materials unavailable to rural

individuals.

7.5. Interdisciplinary Collaboration

This extensive project has successfully overcome challenges found in

both multidisciplinary and international collaborations. We found the five major

challenges to the project were not only due to the complexities of the

international aspect of the problem, as might be expected, but also arose due to

some unexpected difficulties in dealing between the disciplines of engineering,

anthropology, and geology. They are as follows:

• Building, maintaining, and improving rapport between all parties

involved

• Creating project legitimacy in the eyes of all disciplines involved.

• Making and sustaining valuable relationships amongst departmental,

cultural, and intellectual differences

• Cultural sensitivity, including discipline-specific vernacular,

viewpoints, research methods, and principles

• Sustaining future involvement after each aspect of the project is

complete

Re-imagining borders between the disciplines can break down these

hurdles in the way of success. In this section, suggestions and observations,

more adequately described as lessons learned are offered for the improvement

of current and future interdisciplinary, international projects.

88

It may seem obvious that a positive rapport must be achieved for success

when interacting with communities in different countries, but it can be taken for

granted that a rapport must be established and maintained amongst the research

group members. This relationship can be established through group meetings

and maintained through constant communication. Email list serves can facilitate

communication of ideas, concerns, and information. Make sure to include every

team member in important communications and meetings.

When dealing with community members in any setting, one must instill a

feeling of urgency or legitimacy in order to gain support from the community.

This same attitude should be applied to interdisciplinary relationships. In our

project we are chemical engineers working with anthropologists who are helping

to focus our research toward meeting a community’s technological need. The

engineering discipline is traditionally steeped in quantitative data and eschews or

simply does not understand the benefits of qualitative data that anthropological

expertise can provide. It becomes the data owner’s responsibility to relay the

legitimacy of their data with respect to the goals of the project. In asking an

anthropologist to describe their interactions with engineers one can expect a

multitude of responses both positive and negative. These difficulties in

communicating legitimacy between disciplines can easily be overcome.

Start with choosing individuals from other disciplines that have experience

working with your discipline. Often, those with experience have developed

personal ways to overcome these difficulties. In our case, we chose an

anthropologist specialized in applied anthropology in the area of water quality.

89

She is adept at collecting useful qualitative data and especially adept at relaying

that data in a manner that communicates its legitimacy and subsequent

applicability to engineering principles.

Also, make an effort to understand the diverse disciplines involved in the

project. Start by reading publications from the other disciplines. If possible, find

articles pertaining to the research subject. This can give a good idea of what can

be expected out of the research team members. Strides in the direction of

legitimacy and rapport can be made by producing a small amount of high-impact

reading material on the research subject from your field of interest to the team

members from other disciplines.

From the engineering perspective, difficulties can arise when attempting to

explain the importance of numerical data to those who are not on the same

mathematical or scientific level. Patience is key in overcoming this hurdle. In

presenting data, eliminate supporting data that does not directly support the

research findings. Also, detailing experimental procedures when dealing with

nonscientists can be tedious and tiresome for your audience. In this case,

simplification is key in facilitating the legitimacy of your data and suggestions for

further work.

Cultural differences abound in both international and interdisciplinary

relationships. Cultural sensitivity can provide a way to re-imagine and bridge

these boundaries. Languages are not only different from one nation to the next

but also between disciplines. Vernacular from one engineering subject to the

next differs, as well as from engineering to science and social sciences. Reading

90

publications from other disciplines can also help familiarity. Be prepared to

answer questions about the meaning of terms used and do not be shy answering

questions.

Sustaining involvement of all research team members can be a problem in

every endeavor. However, in interdisciplinary work, this problem is exacerbated

by all the aforementioned inherent difficulties. Taking steps to improve rapport,

legitimacy, team relations, and cultural sensitivity can be valuable in sustaining

involvement.

91

Chapter Eight

Conclusions and Future Work

8.1. Summary of Findings

• The three mucilage fractions (GE, CE, and NE) of Opuntia ficus-

indica are efficient flocculants with respect to settling rate when

compared to the flocculating abilities of the widely used chemical

flocculant Al2(SO4)3.

• The GE fraction of the mucilage provides the fastest settling rate of

suspended solids.

• In comparison to Al2(SO4)3, GE flocculates at a rate 3.3 times

faster when both are dosed at 3 mg L-1 in a 5 g L-1 kaolin

slurry.

• GE provides a comparable settling rate to Al2(SO4)3 when

dosed at a concentration 300 times less than the required

amount of Al2(SO4)3.

• The efficiency of the three extracts is directly related to their floc-

forming abilities. GE is a better flocculant because it produces the

largest flocs.

• Settling rates increase with increasing mucilage dose concentrations.

92

• Residual turbidity increases with increasing mucilage dose

concentrations.

• Mucilage doses less than 1 μg L-1 provide comparable residual

turbidities with Al2(SO4)3.

• The GE fraction of Opuntia ficus-indica mucilage is a promising

arsenic removal agent.

• When added to arsenic-contaminated water, GE forms a complex

with the As and floats to the air-water interface.

• Arsenic removals of 33% and 35% were found for systems containing

between 80 and 90 μg L-1 As and dosed with 5 mg L-1 GE.

• 41% removal was found from a system containing high levels of

arsenic (~10 mg L-1) and dosed with high concentrations of GE (~65

mg L-1).

• In this system, the GE-As complex appeared to sink to the

bottom of the water column, suggesting that high levels of As

and high levels of GE perform more closely with the action of

GE and suspended solids.

• Preliminary results suggest the mucilage of Opuntia ficus-indica can

be utilized in filter form as a promising technology for arsenic

removal.

• The abilities of Opuntia ficus-indica to flocculate and remove arsenic

are due to the chemical composition of the three fractions.

93

• The compositions of NE and CE are very similar and show

similar functionality to poly(ethyl cyanoacrylate). It is

suggested that the possible nitrile functionality contributes to

the flocculation abilities.

• The composition of GE is different from that of NE and CE,

and show similar functionality and properties of poly(ethyl

acrylamide). It is suggested that the aliphatic amine

functionality contributes to its abilities in flocculation and

arsenic removal.

• The cultural sensitivity of low income, indigenous communities was

preserved during this study.

• Suggestions for further interdisciplinary endeavors were extracted

from the experiences of this study in the following forms:

• Build rapport

• Create and preserve project legitimacy

• Sustain relationships

• Respect interdiscipline cultural differences

• Sustain future involvement

8.2. Future Work

8.2.1. Mucilage Extraction

Efforts must be implemented in the direction of simplifying the mucilage

extraction procedures. In order for the overall project to succeed in its goals of

94

cultural sensitivity and low socio-cultural impact, the extraction procedure should

be simple enough to be performed in a low-income household.

8.2.2. Flocculation

Optimal dosage schemes must be determined for the combined goals of

fast settling rate and low residual turbidity. Also, different slurry components

should be used to determine the versatility of the mucilage. One of the slurry

components should be sediment from the Temamatla well water.

8.2.3. Arsenic Removal

An intense arsenic removal investigation should be undertaken to elicit the

effects of the following variables on the ability of mucilage to remove arsenic from

contaminated water:

• Arsenic concentration

• Mucilage dose

• System pH

• Mucilage fraction (GE, NE, CE, or simply macerated and filtered

cladodes)

• Temperature

• Conductivity

• Arsenic speciation

95

8.2.4. Filter Design An engineering study is required to determine the appropriate filter design

for combined arsenic and suspended solids removal using Opuntia mucilage.

Some of the design parameters requiring investigation are as follows:

• Filter type

• Filter matrix

• Required throughput

• Required mucilage concentration

• Appropriate regeneration scheme

8.2.5. Temamatla Implementation

The resulting implementable technology will be introduced to the people of

Temamatla and a socio-cultural impact assessment will be performed to

determine the applicability of the technology, as well as the feasibility of the

technology having a sustained impact. Also, the performance of the technology

must be evaluated in a real-world setting.

8.3. Final Remarks

Opuntia ficus-indica mucilage is a promising actor in the field of emerging

technologies for arsenic removal. The implications of this project are exciting.

The possibility of introducing an indigenous material as an improver of quality of

life and health to concerned residents is attractive from a cultural sensitivity and

sustainability standpoint.

96

References

1. Sobsey, M.D., Managing water in the home: accelerated health gains from improved water supply. 2006, (WHO) World Health Organization: Chapel Hill, CA.

2. WHO (World Health Organization), Acceptibility Aspects, in Guidelines for Drinking-water Quality. 2004.

3. Bartram, J., Foreward, in Managing water in the home: accelerated health gains from improved water supply. 2006, (WHO) World Health Organization: Geneva, Switzerland.

4. Smedley, P.L. and D.G. Kinniburgh, Source and Behavior of Arsenic in Groundwater. WHO Arsenic Overview, 2003: p. 1-61.

5. Yamamura, S., J. Bartram, M. Csanady, H.G. Gorchev, and A. Redekopp, Drinking Water Guidelines and Standards. 2003: p. 1-18.

6. Stollenwerk, K.G., Geochemical Processes Controlling Transport of Arsenic in Groundwater: A Review of Adsorption, in Arsenic in Groundwater: Geochemistry and Occurrence, A.H. Welch and K.G. Stollenwerk, Editors. 2003, Kluwer Academic Publishers: Norwell, MA. p. 67-100.

7. NRC (National Research Council), Arsenic in Drinking Water: 2001 Update. 2001, Washington, DC: National Academy Press.

8. WHO (World Health Organization). Water-related diseases. 2001 [cited 2006 April 9]; Available from: http://www.who.int/water_sanitation_health/diseases/arsenicosis/en/print.html.

9. NRC (National Research Council), Arsenic in Drinking Water. 1999, Washington, DC: National Academy Press.

97

10. WHO (World Health Organization). Treating turbid water. Household water treatment and safe storage 2006 [cited 2006 January 29, 2006]; Available from: http://www.who.int/household_water/research/turbidity/en/.

11. Shaban, W.A.R., C.F. Harrington, M. Ayub, and P.J. Harris, A biomaterial based approach for arsenic removal from water. J. Environ. Monit., 2005. 7(4): p. 279-282.

12. EPA (Environmental Protection Agency), Arsenic Treatment Technologies for Soil, Waste, and Water. 2002, Environmental Protection Agency. p. 1-1 - 16-4.

13. Johnston, R., H. Heignen, and P. Wurzel, Chapter 6: Safe Water Technology, in WHO Arsenic Overview. 2001.

14. EPA (Environmental Protection Agency), Regulations on the Disposal of Arsenic Residuals from Drinking Water Treatment Plants. 2000, Office of Research and Development.

15. Tidwell, L.G., J. McCloskey, M. Gale, and P. Miranda. Technologies and Potential Technologies for Removing Arsenic from Process and Mine Wastewater. in REWAS '99. 1999. San Sebastian, Spain.

16. EPA (Environmental Protection Agency), Technologies and Costs for Removal of Arsenic from Drinking Water. 2000, Environmental Protection Agency.

17. Ahmed, M.F. An Overview of Arsenic Removal Technologies in Bangladesh and India. in BUET-UNU International Workshop on Technologies for Arsenic Removal from Drinking Water. 2001. Dhaka, Bangladesh.

18. Pierce, M.L. and C.B. Moore, Adsorption of Arsenite and Arsenate on amorphous iron hydroxide. Water Resources, 1982. 16: p. 1247-1253.

19. Rapid Assesment of Household Level Arsenic Removal Technologies - Bangladesh Executive Summary. 2001, BAMWSP, DFID, WaterAid. p. 1-24.

20. Mok, W.M. and C.M. Wai, Mobilization of Arsenic in Contaminated River Water, in Arsenic in the Environment, J.O. Niragu, Editor. 1994, John Wiley & Sons, Inc.: New York.

98

21. Sarkar, A.R. and O.T. Rahman. In-situ Removal of Arsenic-Experiences of DPHE-Danida Pilot Project. in BUET-UNU International Workshop on Technologies for Arsenic Removal From Drinking Water. 2001. Dhaka, Bangladesh.

22. Young, E., Cleaning up arsenic and old waste (using sunlight and air to remove arsenic). New Scientist, 1996. 152: p. 22.

23. Sharmin, N. Arsenic Removal Processes on Trial in Bangladesh. in BUET-UNU International Workshop on Technologies for Arsenic Removal from Drinking Water. 2001. Dhaka, Bangladesh.

24. Oh, J.I., K. Yamamoto, H. Kitawaki, S. Nakao, T. Sugawara, M.M. Rahman, and M.H. Rahman, Application of low-pressure nanofiltration coupled with a bicycle pump for the treatment of arsenic-contaminated groundwater. Desalination, 2000. 132: p. 307-314.

25. Hoque, B.A., M.M. Hoque, T. Ahmed, S. Islam, A.K. Azad, N. Ali, M. Hossain, and M.S. Hossain, Demand-based water options for arsenic mitigation: an experience from rural Bangladesh. Public Health, 2004. 118: p. 70-77.

26. Simeonova, V.P., Pilot study for arsenic removal. Water Supply, 2000. 18(1/2): p. 636-640.

27. Carrillo, A. and J.I. Derever, Adsorption of arsenic by natural aquifer material in the San Antonio-El Triunfo mining area, Baha California, Mexico. Environ. Geol., 1998. 35(4).

28. Ongley, L.K., M.A. Armienta, K. Heggeman, and A.S. Lathrop, Arsenic removal from contaminated water by the Soyatal Formation, Zimapán Mining District, Mexico - a potential low-cost low-tech remediation system. Geochemistry: Exploration, Environment, Analysis, 2001. 1(1): p. 23-31.

29. Elizalde-González, M.P., A.J. Mattuschb, and R. Wennrich, Application of natural zeolites for preconcentration of arsenic species in water samples. J. Environ. Monit., 2001. 3: p. 22-26.

30. Pinon-Miramontes, M., R.G. Bautista-Margulis, and A. Perez-Hernandez, Removal of arsenic and fluoride from drinking water with cake alum and a polymeric anionic flocculant. Fluoride, 2003. 36(2): p. 122-128.

99

31. Gutierrez-Avila, h., S. Becerra-Winkler, H. Brust-Carmona, J. Juarez-Mendoza, and J. Juarez Patino, Removal of arsenic from water for humna consumption in homes in rural communities in the Comarca Lagunera, Mexico. Salud Pública de México, 1998. 31(3).

32. Parga, J.R., D.L. Cocke, J.L. Valenzuela, and J.A. Gomes, Arsenic removal via electrocoagulation from heavy metal contaminated groundwater in La Comarca Lagunera, México. Journal of Hazardous Materials, 2005. B124: p. 247-254.

33. Clifford, D. and C.C. Lin, Arsenic(3) and arsenic (5) removal from drinking water in San Ysidro, New Mexico. 1991, EPA (Environmental Protection Agency): Cincinnatti, OH. p. 119.

34. Flores-Tavizón, E., M.T. Alarcón-Herrera, E. González, and E.J. Olguín, Arsenic Tolerating Plants from Mine Sites and Hot Springs in the Semi-Arid Region of Chihuahua, Mexico. Acta Biotechnol., 2003. 23(2-3): p. 113-119.

35. Razo, I., L. Carrizales, J. Castro, F. Diaz-Barriga, and M. Monroy, Arsenic and Heavy Metal Pollution of Soil, Water, and Sediments in Semi-Arid Climate Mining Area in Mexico. Water, Air, & Soil Polution, 2004. 152(1-4): p. 129-152.

36. Armienta, M.A., G. Villaseñor, R. Rodríguez, L.K. Ongley, and H. Mango, The role of arsenic-bearing rocks in groundwater pollution at Zimapán Valley, México. Environ. Geol., 2001. 40: p. 571-581.

37. Mejía, J., L. Carrizales, V.M. Rodríguez, M.E. Jiménez-Capdeville, and F. Díaz-Barriga, Un método para la evaluación para la salud en zonas mineras. Salud Pública de México, 1999. 42: p. 132-140.

38. Méndez, M. and M.A. Armienta, Arsenic phase distribution in Zimapán mine tailings, Mexico. Geofísica Internacional, 2003. 42(1): p. 131-140.

39. Armienta, M.A., R. Rodríguez, A. Aguayo, N. Ceniceros, G. Villaseñor, and O. Cruz, Arsenic Contamination of Groundwater at Zimapán, Mexico. Hydrogeology Journal, 1997. 5(2): p. 39-46.

100

40. Del Razo, L.M., G.G. Garcia-Vargas, J. Garcia-Salcedo, M.F. Sanmiguel, M. Rivera, M.C. Hernandez, and M.E. Cebrian, Arsenic levels in cooked food and assessment of adult dietary intake of arsenic in the Region Lagunera, Mexico. Food and Chemical Toxicology, 2002. 40: p. 1423-1431.

41. Pineda-Zavaleta, A.P., G. García-Vargas, V.H. Borja-Aburto, L.C. Acosta-Saavedra, E.V. Aguilar, A. Gómez-Munoz, M.E. Cebrián, and E.S. Calderón-Aranda, Nitric oxide and superoxide anion production in monocytes from children exposed to arsenic and lead in region Lagunera, Mexico. Toxicology and Applied Pharmacology, 2004. 198: p. 283-290.

42. Hewitt, W.P., Hierve el Agua, Mexico: Its Water and Its Corn-Growing Potential. Latin American Antiquity, 1994. 5(2): p. 177-181.

43. Elless, M.P., C.Y. Poynton, C.A. Willms, M.P. Doyle, A.C. Lopez, D.A. Sokkary, B.W. Ferguson, and M.J. Blaylock, Pilot-scale deomonstration of phytofiltration for treatment of arsenic in New Mexico drinking water. Water Research, 2005. 39: p. 3863-3872.

44. Katsoyiannis, I.A. and A.I. Zouboulis, Application of biological processes for the removal of arsenic from groundwaters. Water Research, 2004. 38(1): p. 17-26.

45. Sáenz, C., E. Sepúlveda, and B. Matsuhiro, Opuntia spp mucilage's: a functional component with industrial perspectives. Journal of Arid Env., 2004. 57(3): p. 275-290.

46. Mohammed-Yaseen, Y., S.A. Barringer, and W.E. Splittstoesser, A note on the uses of Opuntia spp. in Central/North America. Journal of Arid Env., 1996. 32: p. 347-353.

47. Felker, P. and P. Inglese, Short-Term and Long-Tem Research Needs for Opuntia ficus-indica (L.) Mill. Utilization in Arid Areas. J. PACD, 2003: p. 131-152.

48. Bailey, L.H., Hortus-Third. 1976, New York: MacMillan Publishing Co. 1290.

49. Villareal, F., P. Ropjas-Mendoz, V. Arellano, and J. Moreno, Chemical studies on six cactus (nopal) species. Science, 1963. 22: p. 75-82.

101

50. Rodriguez-Felix, A. and M. Cantwell, Developmental changes to composition and quality of prickly pear cactus cladodes (nopalitos). Plants, Food, and Human Nutrition, 1988. 38: p. 83-93.

51. Russell, C.E. and P. Felker, The prickly pear (Opuntia spp., Cactaceae): A source of human and animal food in semi-arid regions. Economic Botany, 1987. 41: p. 433-445.

52. Amin, E.S., O.M. Awad, and M.M. El-Sayed, The mucilage of Opuntia ficus indica. Carbohydrate Research, 1970. 15: p. 159-161.

53. Trachtenberg, S. and A.M. Mayer, Composition and properties of Opunita ficus indica mucilage. Phytochemistry, 1981. 20: p. 2885-2668.

54. Cárdenas, A., I. Higuera-Ciapara, and F. Goycoolea, Rheology and aggregation of cactus (Opuntia ficus indica) mucilage in solution. J. PACD, 1997. 2: p. 152-159.

55. Medina-Torres, L., E. Birto-De La Fuente, B. Torrestiana-Sanchez, and R. Katthain, Rheological properties of the mucilage gum (Opuntia ficus indica). Food Hydrocolloids, 2000. 14(5): p. 417-424.

56. Madjoub, H., S. Roudesli, L. Piction, D. Le Cerf, G. Muller, and M. Grissel, Prickly pear nopals pectins from Opuntia ficus indica physico-chemical study in dilute and semi-dilute solutions. Carbohydrate Polymers, 2001. 46: p. 69-79.

57. Trachtenberg, S. and A. Mayer, Biophysical properties of Opuntia ficus indica mucilage. Phytochemistry, 1982. 21: p. 2835.

58. McGarvie, D. and P.H. Parolis, Methylation analysis of the mucilage of Opuntia ficus indica. Carbohydrate Research, 1981. 88: p. 305-314.

59. McGarvie, D. and P.H. Parolis, The acid-labile, peripheral chains of the mucilage of Opuntia ficus indica. carbohydrate Research, 1981. 94: p. 57-65.

60. McGarvie, D. and P.H. Parolis, The mucilage of Opuntia ficus indica. Carbohydrate Research, 1979. 69: p. 171-179.

102

61. Paulsen, B.S. and P.S. Lund, Water-soluble polysaccharides of Opuntia ficus indica cv "Burbank's Spineless". Phytochemistry, 1979. 18: p. 569-571.

62. Saag, K.M.L., G. Sanderson, P. Moyna, and G. Ramos, Cactaceae mucilage composition. Journal of the Science of Food and Agriculture, 1975. 26: p. 993-1000.

63. Goycoolea, F.M. and A. Cárdenas, Pectins from Opuntia spp: A Short Review. J. PACD, 2003: p. 17-29.

64. Sáenz, C.H., Cladodes: a Source of Dietary Fiber. J. PACD, 1997.

65. Galati, E.M., M.R. Modello, M.T. Monforte, M. Ggalluzzo, N. Miceli, and M.M. Tripodo, Effect of Opuntia ficus-indica (L.) Mill. Cladodes in the Wound-Healing Process. J. PACD, 2003.

66. Fernandez, M.L., A. Trejo, and D. McNamara, Pectin isolated from prickly pear (Opuntia sp.) modifies low density lipoprotein metabolism in cholesterol-fed guineq pigs. J. Nutrition, 1990. 120: p. 1293-1290.

67. Fernandez, M.L., E.C.K. Lin, A. Trejo, and D. McNamara, Prickly Pear (Opuntia sp.) pectin reverses low density lipoprotein receptor suppression induced by a hypercholesterolemic diet in guinea pigs. J. Nutrition, 1992. 122: p. 2330-2340.

68. Fernandez, M.L., E.C.K. Lin, and A. Trejo, Prickly pear (Opuntia sp.) pectin alters hepatic cholesterol metabolism without affecting cholesterol absorption in guinea pigs fed a hypercholesterolemic diet. J. Nutrition, 1994. 124: p. 817-824.

69. Cardenas, M.L., S. Serna, and J. Velasco de la Garza, Effect of raw and cooked nopal (Opuntia ficus-indica) ingestion on growth and total cholesterol lipoproteins and blood glucose in rats. Archivos Latinoamericanos de Nutricion, 1998. 48(4): p. 316-323.

70. El Kossori, R.L., C. Sachez, E.S. El Boustani, N. Maucourt, Y. Sauvaire, L.K. Mejean, and C. Villaume, Comparison of the effects of prickly pear (Opuntia ficus-indica sp.) fruit, arabic gum, carrageenan, alginic acid, locust bean gum and citrus pectin on viscosity and in vitro digestibility of casein. J. Sci. Food. Agric., 2000. 80: p. 359-364.

103

71. Galati, E.M., N. Pergolizzi, M.T. Monforte, and M.N. Tripodo, Study on the increment of the production of gastric mucus in rats treated with Opuntia ficus indica (L.) Mill. Cladodes. Journal of Ethnopharmacol., 2002. 83: p. 229-233.

72. Cárdenas, A., W.M. Arguelles, and F.M. Goycoolea, On the Possible Role of Opuntia ficus-indica Mucilage in Lime Mortar Performance in the Protection of Historical Buildings. J. PACD, 1998.

73. Garti, N., Hydrocolloids as emulsifying agents for oil-water emulsions. Journal of Dispersion Sci. Technol., 1999. 20((1&2)): p. 327-355.

74. Frati-Munari, A.C., E. Jimenez, and C.R. Ariza, Hypoglycemic effects of Opuntia ficus indica in non-insulin dependent diabetes mellitus patients. Phytotherapy Research, 1990. 4: p. 195-197.

75. Park, E.H. and M.J. Chun, Wound healing activity of Opuntia ficus-indica. Fitoterapia, 2001. 72: p. 165-167.

76. Nyquist, R.A. and R.O. Kagel, Organic Materials, in Infrared and Raman Spectroscopy, E.G. Brame and J.G. Grasselli, Editors. 1977, Marcel Dekker, Inc.: New York. p. 442 - 565.

77. Tripathy, T., S.R. Pandey, N.C. Karmakar, R.P. Bhagat, and R.P. Singh, Novel flocculating agent based on sodium alginate and acrylamide. European Polymer Journal, 1999. 35(11): p. 2057-2072.

78. Karmakar, G.P. and R.P. Singh, Flocculation studies using amylose-grafted polyacrylamide. Colloids and Surfaces A: Physiochemical and Engineering Aspects, 1998. 133(1-2): p. 119-124.

79. Tripathy, T. and R.P. Singh, High performance flocculating agent basesd on partially hydrolysed sodium alginate-g-polyacrylamide. European Polymer Journal, 2000. 36(7): p. 1471-1476.

80. Nayak, B.R. and R.P. Singh, Comparative studies on the flocculation characteristics of polyacrylamide grafted guar gum and hydroxypropyl guar gum. Polymer International, 2001. 50(8): p. 875-884.

104

81. Besra, L., D.K. Sengupta, S.K. Roy, and P. Ay, Studies on flocculation and dewatering of kaolin suspensions by anionic polyacrylamide flocculant in the presence of some surfactants. Internationa Journal of Mineral Processing, 2002. 66(1-4): p. 1-28.

82. Besra, L., D.K. Sengupta, S.K. Roy, and P. Ay, Influence of surfactants on flocculation and dewatering of kaolin suspensions by cationic polyacrylamide (PAM-C) flocculant. Separation and Purification Technology, 2003. 30(3): p. 251-264.

83. Besra, L., D.K. Sengupta, S.K. Roy, and P. Ay, Influence of polymer adsorption and conformation on flocculation and dewatering of kaolin suspensions. Separation and Purification Technology, 2004. 37(3): p. 231-246.

84. Singh, R.P., B.R. Nayak, D.R. Biswal, T. Tripathy, and K. Banik, Biobased polymeric flocculants for industrial effluent treatment. Materials Research Innovations, 2003. 7(5): p. 331-340.

85. Zhao, Y.Q., Settling behaviour of polymer flocculated water-treatment sludge II: effects of floc structure and floc packing. Separation and Purification Technology, 2004. 35(3): p. 175-183.

86. Qian, J.W., X.J. Xiang, W.K. Yang, M. Wang, and B.Q. Zheng, Flocculation performance of different polyacrylamide and the relation between optimal dose and critical concentration. European Polymer Journal, 2004. 40(8): p. 1699-1704.

87. Rath, S.K. and R.P. Singh, Flocculation characteristics of grafted and ungrafted starch, amylose, and amylopectin. Journal of Applied Polymer Science, 1997. 66(9): p. 1721-1729.

88. Karmakar, N.C., S.K. Rath, B.S. Sastry, and R.P. Singh, Investigation on flocculation characteristics of polysaccharide-based graft copolymers in coal fines suspension. Journal of Applied Polymer Science, 1998. 70(13): p. 2619-2625.

89. Rath, S.K. and R.P. Singh, Grafted amylopectin: applications in flocculation. Colloids and Surfaces A: Physiochemical and Engineering Aspects, 1998. 139(2): p. 129-135.

105

90. Pan, J.R., C. Hyang, S. Chen, and Y.C. Chung, Evaluation of a modified chitosan biopolymer for coagulation of colloidal particles. Colloids and Surfaces A: Physiochemical and Engineering Aspects, 1999. 147(3): p. 359-364.

91. Tripathy, T., R.P. Bhagat, and R.P. Singh, The flocculation performance of grafted sodium alginate and other polymeric flocculants in relation to iron ore slime suspension. European Polymer Journal, 2001. 37(1): p. 125-130.

92. Tripathy, T., N.C. Karmakar, and R.P. Singh, Development of novel polymeric flocculant based on grafted sodium alginate for the treatment of cole mine wastewater. Journal of Applied Polymer Science, 2001. 82(2): p. 375-382.

93. Wang, D. and H. Tang, Modified Inorganic Polymer Flocculant-PFSi: Its Preparation, Characterization and Coagulation Behavior. Water Research, 2001. 35(14): p. 3418-3428.

94. Kan, C., C. Huang, and J.R. Pan, Time requirement for rapid-mixing in coagulation. Colloids and Surfaces A: Physiochemical and Engineering Aspects, 2002. 203(1-3): p. 1-9.

95. Nonaka, T., H. Li, K. Makinose, T. Ogata, and S. Kurihara, Synthesis and functions of water-soluble and thermosensitive copolymers having phosphonium groups from acryloyloxyethyl trialkyl phosphonium chloride, N-isopropylacrylamide, and without/with butylmethacrylate. Journal of Applied Polymer Science, 2003. 90(4): p. 1139-1147.

96. Lee, J.F., P.M. Liau, D.H. Seng, and P.T. Wen, Behavior of organic polymers in drinking water purification. Chemosphere, 1998. 37(6): p. 1045-1061.

97. Scientific, H., Micro 100 Manual. 2004: Fort Myers. p. 15.

98. McCarthy, K.T., T. Pichler, and R.E. Price, Geochemistry of Champagne Hot Springs shallow hydrothermal vent field and associated sediments, Dominica, Lesser Antilles. Chemical Geology, 2005. 224: p. 55-68.

99. Price, R.E., Abundance and Mineralogical Associations of Naturally Occurring Arsenic in the Upper Floridan Aquifer, Suwanee Limestone, in Department of Geology. 2003, University of South Florida: Tampa. p. 74.

106

100. Welz, B. and M. Sperling, Atomic Absorption Spectrometry. 3 ed. 1999, New York: Wiley-VCH. 941.

101. Munk, P. and T.M. Aminabhavi, Introduction to Macromolecular Science. 2 ed. 2002, New York: Wiley-Interscience. 609.

107

Appendices

108

Appendix A: Cylinder and Jar Tests Sample Dosage Schemes

Table 9: Flocculant Doses for 100 ml Graduated Cylinder Tests from Prepared 1 g L-1 Stock Solutions of Flocculants.

Desired Final Flocculant

Concentration

AppropriateDose

Volume [mg L-1] Into the

0.01 0.001 0.1 0.01 1 0.1 2 0.2 3 0.3 4 0.4 5 0.5 10 1.0

Table 10: Flocculant Doses for Each 0.5 L Jar Test Compartment from Prepared

1 g L-1 Stock Solutions of Flocculants.

Desired Final Flocculant

Concentration

AppropriateDose

Volume [mg L-1] [ml]

0.01 0.005 0.1 0.05

0.25 0.125 0.5 0.25 1 0.5 2 1 3 1.5 4 2 5 2.5 10 5

Appendix B: Material Safety Data Sheets

B.1. Aluminum Sulfate

ALUMINUM SULFATE

1. Product Identification Synonyms: Sulfuric acid, aluminum salt (3:2), octadeca hydrate; Cake alum; Patent alum CAS No.: 10043-01-3 (Anhydrous) 7784-31-8 (Octadecahydrate) Molecular Weight: 666.44 Chemical Formula: Al2(SO4)3.18H2O Product Codes: J.T. Baker: 0564 Mallinckrodt: 3208

2. Composition/Information on Ingredients Ingredient CAS No Percent Hazardous --------------------------------------- ------------ ------------ --------- Aluminum Sulfate 10043-01-3 98 - 100% Yes

3. Hazards Identification Emergency Overview -------------------------- WARNING! HARMFUL IF SWALLOWED OR INHALED. CAUSES IRRITATION TO SKIN, EYES AND RESPIRATORY TRACT. SAF-T-DATA(tm) Ratings (Provided here for your convenience) ----------------------------------------------------------------------------------------------------------- Health Rating: 2 - Moderate Flammability Rating: 0 - None Reactivity Rating: 1 - Slight Contact Rating: 2 - Moderate Lab Protective Equip: GOGGLES; LAB COAT; VENT HOOD; PROPER GLOVES Storage Color Code: Green (General Storage) -----------------------------------------------------------------------------------------------------------

109

Appendix B (Continued) Potential Health Effects ---------------------------------- This material hydrolyzes in water to form sulfuric acid, which is responsible for the irritating effects given below. Inhalation: Causes irritation to the respiratory tract. Symptoms may include coughing, shortness of breath. Ingestion: Causes irritation to the gastrointestinal tract. Symptoms may include nausea, vomiting and diarrhea. There have been two cases of fatal human poisonings from ingestion of 30 grams of alum. Skin Contact: Causes irritation to skin. Symptoms include redness, itching, and pain. Eye Contact: Causes irritation, redness, and pain. Chronic Exposure: No information found. Aggravation of Pre-existing Conditions: No information found.

4. First Aid Measures Inhalation: Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical attention. Ingestion: If swallowed, DO NOT INDUCE VOMITING. Give large quantities of water. Never give anything by mouth to an unconscious person. Get medical attention immediately. Skin Contact: Wipe off excess material from skin then immediately flush skin with plenty of water for at least 15 minutes. Remove contaminated clothing and shoes. Get medical attention. Wash clothing before reuse. Thoroughly clean shoes before reuse. Eye Contact: Immediately flush eyes with plenty of water for at least 15 minutes, lifting upper and lower eyelids occasionally. Get medical attention.

5. Fire Fighting Measures Fire: Not considered to be a fire hazard.

110

Appendix B (Continued) Explosion: Not considered to be an explosion hazard. Fire Extinguishing Media: Keep in mind that addition of water can cause the formation of sulfuric acid. Special Information: In the event of a fire, wear full protective clothing and NIOSH-approved self-contained breathing apparatus with full facepiece operated in the pressure demand or other positive pressure mode.

6. Accidental Release Measures Ventilate area of leak or spill. Keep unnecessary and unprotected people away from area of spill. Wear appropriate personal protective equipment as specified in Section 8. Spills: Pick up and place in a suitable container for reclamation or disposal, using a method that does not generate dust. Cover spill with sodium bicarbonate or soda ash and mix. US Regulations (CERCLA) require reporting spills and releases to soil, water and air in excess of reportable quantities. The toll free number for the US Coast Guard National Response Center is (800) 424-8802.

7. Handling and Storage Keep in a tightly closed container, stored in a cool, dry, ventilated area. Protect against physical damage. Isolate from incompatible substances. Aluminum sulfate absorbs moisture and becomes a safety hazard when spilled because it absorbs moisture and becomes slippery. Containers of this material may be hazardous when empty since they retain product residues (dust, solids); observe all warnings and precautions listed for the product.

8. Exposure Controls/Personal Protection Airborne Exposure Limits: -OSHA Permissible Exposure Limit (PEL): 2 mg/m3 (TWA) soluble salts as Al -ACGIH Threshold Limit Value (TLV): 2 mg/m3 (TWA) soluble salts as Al Ventilation System: A system of local and/or general exhaust is recommended to keep employee exposures below the Airborne Exposure Limits. Local exhaust ventilation is generally preferred because it can control the emissions of the contaminant at its source, preventing dispersion of it into the general work area. Please refer to the ACGIH document, Industrial Ventilation, A Manual of Recommended Practices, most recent edition, for details.

111

Appendix B (Continued) Personal Respirators (NIOSH Approved): If the exposure limit is exceeded and engineering controls are not feasible, a half facepiece particulate respirator (NIOSH type N95 or better filters) may be worn for up to ten times the exposure limit or the maximum use concentration specified by the appropriate regulatory agency or respirator supplier, whichever is lowest.. A full-face piece particulate respirator (NIOSH type N100 filters) may be worn up to 50 times the exposure limit, or the maximum use concentration specified by the appropriate regulatory agency, or respirator supplier, whichever is lowest. If oil particles (e.g. lubricants, cutting fluids, glycerine, etc.) are present, use a NIOSH type R or P filter. For emergencies or instances where the exposure levels are not known, use a full-facepiece positive-pressure, air-supplied respirator. WARNING: Air-purifying respirators do not protect workers in oxygen-deficient atmospheres. Skin Protection: Wear impervious protective clothing, including boots, gloves, lab coat, apron or coveralls, as appropriate, to prevent skin contact. Eye Protection: Use chemical safety goggles and/or full face shield where dusting or splashing of solutions is possible. Maintain eye wash fountain and quick-drench facilities in work area.

9. Physical and Chemical Properties Appearance: Colorless crystals. Odor: Odorless. Solubility: 87 g/100 cc water @ 0C (32F). Specific Gravity: 1.69 @ 17C/4C pH: No information found. % Volatiles by volume @ 21C (70F): 0 Boiling Point: No information found. Melting Point: 87C (189F) Decomposes.

112

Appendix B (Continued) Vapor Density (Air=1): No information found. Vapor Pressure (mm Hg): No information found. Evaporation Rate (BuAc=1): No information found.

10. Stability and Reactivity Stability: Stable under ordinary conditions of use and storage. Hazardous Decomposition Products: Hydrolyzes to form dilute sulfuric acid. Toxic and corrosive oxides of sulfur may be formed when heated to decomposition. Hazardous Polymerization: Will not occur. Incompatibilities: Corrosive to metals in the presence of water. Conditions to Avoid: Moisture and incompatibles.

11. Toxicological Information Anhydrous Material: Oral mouse LD50: 6207 mg/kg; Irritation eyes rabbit: 10 mg/24H severe; investigated as a mutagen and reproductive effector. 18-Hydrate: Oral mouse LD50: > 9 gm/kg; investigated as a mutagen. --------\Cancer Lists\------------------------------------------------------ ---NTP Carcinogen--- Ingredient Known Anticipated IARC Category ------------------------------------ ----- ----------- ------------- Aluminum Sulfate (10043-01-3) No No None

12. Ecological Information Environmental Fate: No information found. Environmental Toxicity: No information found.

113

Appendix B (Continued) 13. Disposal Considerations Whatever cannot be saved for recovery or recycling should be managed in an appropriate and approved waste disposal facility. Processing, use or contamination of this product may change the waste management options. State and local disposal regulations may differ from federal disposal regulations. Dispose of container and unused contents in accordance with federal, state and local requirements.

14. Transport Information Not regulated.

15. Regulatory Information --------\Chemical Inventory Status - Part 1\--------------------------------- Ingredient TSCA EC Japan Australia ----------------------------------------------- ---- --- ----- --------- Aluminum Sulfate (10043-01-3) Yes Yes Yes Yes --------\Chemical Inventory Status - Part 2\--------------------------------- --Canada-- Ingredient Korea DSL NDSL Phil. ----------------------------------------------- ----- --- ---- ----- Aluminum Sulfate (10043-01-3) Yes Yes No No --------\Federal, State & International Regulations - Part 1\---------------- -SARA 302- ------SARA 313------ Ingredient RQ TPQ List Chemical Catg. ----------------------------------------- --- ----- ---- -------------- Aluminum Sulfate (10043-01-3) No No No No --------\Federal, State & International Regulations - Part 2\---------------- -RCRA- -TSCA- Ingredient CERCLA 261.33 8(d) ----------------------------------------- ------ ------ ------ Aluminum Sulfate (10043-01-3) 5000 No No Chemical Weapons Convention: No TSCA 12(b): No CDTA: No SARA 311/312: Acute: Yes Chronic: No Fire: No Pressure: No Reactivity: No (Mixture / Solid) Australian Hazchem Code: None allocated. Poison Schedule: None allocated.

114

Appendix B (Continued) WHMIS: This MSDS has been prepared according to the hazard criteria of the Controlled Products Regulations (CPR) and the MSDS contains all of the information required by the CPR.

16. Other Information NFPA Ratings: Health: 2 Flammability: 0 Reactivity: 0 Label Hazard Warning: WARNING! HARMFUL IF SWALLOWED OR INHALED. CAUSES IRRITATION TO SKIN, EYES AND RESPIRATORY TRACT. Label Precautions: Avoid breathing dust. Keep container closed. Use only with adequate ventilation. Wash thoroughly after handling. Avoid contact with eyes, skin and clothing. Label First Aid: If swallowed, DO NOT INDUCE VOMITING. Give large quantities of water. Never give anything by mouth to an unconscious person. If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. In case of contact, wipe off excess material from skin then immediately flush eyes or skin with plenty of water for at least 15 minutes. Remove contaminated clothing and shoes. Wash clothing before reuse. In all cases, get medical attention. Product Use: Laboratory Reagent. Revision Information: No Information Found. Disclaimer: ************************************************************************************************ Mallinckrodt Baker, Inc. provides the information contained herein in good faith but makes no representation as to its comprehensiveness or accuracy. This document is intended only as a guide to the appropriate precautionary handling of the material by a properly trained person using this product. Individuals receiving the information must exercise their independent judgment in determining its appropriateness for a particular purpose. MALLINCKRODT BAKER, INC. MAKES NO REPRESENTATIONS OR WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE WITH RESPECT TO THE INFORMATION SET FORTH HEREIN OR THE PRODUCT TO WHICH THE INFORMATION REFERS. ACCORDINGLY, MALLINCKRODT BAKER, INC. WILL NOT BE

115

116

Appendix B (Continued) RESPONSIBLE FOR DAMAGES RESULTING FROM USE OF OR RELIANCE UPON THIS INFORMATION. ************************************************************************************************ Prepared by: Environmental Health & Safety Phone Number: (314) 654-1600 (U.S.A.)

117

Appendix B (Continued)

B.2. Arsenic(III) Oxide Material Safety Data Sheet Arsenic (III) Oxide, 99.999% ACC# 99309

Section 1 - Chemical Product and Company Identification

MSDS Name: Arsenic (III) Oxide, 99.999% Catalog Numbers: AC192490000, AC192490050 Synonyms: Arsenic oxide; Arsenic sesquioxide; Arsenous oxide; Arsenous acid anhydride; Arsenous acid. Company Identification: Acros Organics N.V. One Reagent Lane Fair Lawn, NJ 07410 For information in North America, call: 800-ACROS-01 For emergencies in the US, call CHEMTREC: 800-424-9300

Section 2 - Composition, Information on Ingredients

CAS# Chemical Name Percent EINECS/ELINCS1327-53-3 Arsenic trioxide 99.999 215-481-4

Section 3 - Hazards Identification

EMERGENCY OVERVIEW Appearance: white solid. Danger! May be fatal if swallowed. Cancer hazard. Poison! Contains inorganic arsenic. Harmful if inhaled. Causes eye and skin irritation. May cause severe respiratory and digestive tract irritation with possible burns. May cause central nervous system effects. May cause blood abnormalities. May cause lung damage. May cause cardiac disturbances. May cause liver and kidney damage. This substance has caused adverse reproductive and fetal effects in animals. Target Organs: Kidneys, central nervous system, liver, lungs, cardiovascular system, red blood cells, skin.

118

Appendix B (Continued) Potential Health Effects Eye: Contact produces irritation, tearing, and burning pain. May cause conjunctivitis. Skin: Causes irritation with burning pain, itching, and redness. May cause dermatitis. Exposure to arsenic compounds may produce hyperpigmentation of the skin and hyperkeratoses of plantar and palmar surfaces as well as both primary irritation and sensitization types. Ingestion: May be fatal if swallowed. Causes severe digestive tract burns with abdominal pain, vomiting, and possible death. May cause hemorrhaging of the digestive tract. Ingestion of arsenical compounds may cause burning of the lips, throat constriction, swallowing difficulties, severe abdominal pain, severe nausea, projectile vomiting, and profuse diarrhea. Ingestion of arsenic compounds can produce convulsions, coma, and possibly death within 24 hours. Inhalation: May cause severe irritation of the respiratory tract with sore throat, coughing, shortness of breath and delayed lung edema. Inhalation of arsenic compounds may lead to irritation of the respiratory tract and to possible nasal perforation. Long-term exposure to arsenic compounds may produce impairment of peripheral circulation. Chronic: May cause liver and kidney damage. Chronic inhalation may cause nasal septum ulceration and perforation. May cause anemia and other blood cell abnormalities. Chronic skin effects include: cracking, thickening, pigmentation, and drying of the skin. Arsenic trioxide can cause cancer in humans. Other long term effects include: anemia, liver and kidney damage. Chronic exposure to arsenical dust may cause shortness of breath, nausea, chest pains, and garlic odor.

Section 4 - First Aid Measures

Eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid. Skin: Get medical aid. Flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse. Ingestion: Call a poison control center. If swallowed, do not induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an unconscious person. Get medical aid.

119

Appendix B (Continued) Inhalation: Remove from exposure and move to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid. Do NOT use mouth-to-mouth resuscitation. Notes to Physician: Treat symptomatically and supportively.

Section 5 - Fire Fighting Measures

General Information: As in any fire, wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion. Use extinguishing media appropriate to the surrounding fire. Substance is noncombustible. Extinguishing Media: Substance is noncombustible; use agent most appropriate to extinguish surrounding fire. Do NOT get water inside containers. Flash Point: Not applicable. Autoignition Temperature: Not applicable. Explosion Limits, Lower:Not available. Upper: Not available. NFPA Rating: (estimated) Health: 3; Flammability: 0; Instability: 0

Section 6 - Accidental Release Measures

General Information: Use proper personal protective equipment as indicated in Section 8. Spills/Leaks: Vacuum or sweep up material and place into a suitable disposal container. Avoid runoff into storm sewers and ditches which lead to waterways. Clean up spills immediately, observing precautions in the Protective Equipment section. Avoid generating dusty conditions. Provide ventilation. Do not get water inside containers.

Section 7 - Handling and Storage

Handling: Wash thoroughly after handling. Remove contaminated clothing and wash before reuse. Minimize dust generation and accumulation. Avoid contact with eyes, skin, and clothing. Avoid ingestion and inhalation. Do not allow contact with water. Use only with adequate ventilation or respiratory protection. Storage: Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances. Do not store in metal containers.

120

Appendix B (Continued)

Section 8 - Exposure Controls, Personal Protection

Engineering Controls: Use adequate general or local exhaust ventilation to keep airborne concentrations below the permissible exposure limits. See 29CFR 1910.1018 for regulatory requirements pertaining to all occupational exposures to inorganic arsenic. Exposure Limits

Chemical Name ACGIH NIOSH OSHA - Final PELs

Arsenic trioxide 0.01 mg/m3 TWA (listed under Arsenic).

5 mg/m3 IDLH (listed under Arsenic).5 mg/m3 IDLH (as As) (listed under Arsenic, inorganic compounds).

0.5 mg/m3 TWA (listed under Arsenic).5 æg/m3 Action Level (as As); 10 æg/m3 PEL (as As. Cancer hazard - see 29 CFR 1 910.1018. Arsine excepted) (listed under Arsenic, inorganic compounds).

OSHA Vacated PELs: Arsenic trioxide: No OSHA Vacated PELs are listed for this chemical. Personal Protective Equipment Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure. Respirators: Follow the OSHA respirator regulations found in 29 CFR 1910.134 or European Standard EN 149. Use a NIOSH/MSHA or European Standard EN 149 approved respirator if exposure limits are exceeded or if irritation or other symptoms are experienced.

121

Appendix B (Continued)

Section 9 - Physical and Chemical Properties

Physical State: Solid Appearance: white Odor: odorless pH: Not available. Vapor Pressure: 66 mm Hg @ 312C Vapor Density: Not available. Evaporation Rate:Negligible. Viscosity: Not available. Boiling Point: 465 deg C Freezing/Melting Point:312 deg C Decomposition Temperature:Not available. Solubility: 3.7% in water. Specific Gravity/Density: 3.738 Molecular Formula:As2O3 Molecular Weight:197.84

Section 10 - Stability and Reactivity

Chemical Stability: Stable under normal temperatures and pressures. Conditions to Avoid: Dust generation, moisture, metals, excess heat. Incompatibilities with Other Materials: Incompatible with chlorine trifluoride, fluorine, hydrogen fluoride, oxygen difluoride, and sodium chlorate. Can generate arsine, which is an extremely poisonous gas, when arsenic compounds contact acid, alkalies, or water in the presence of an active metal (zinc, aluminum, magnesium, manganese, sodium, iron, etc). Hazardous Decomposition Products: Irritating and toxic fumes and gases, oxides of arsenic, arsine. Hazardous Polymerization: Has not been reported.

122

Appendix B (Continued)

Section 11 - Toxicological Information

RTECS#: CAS# 1327-53-3: CG3325000 LD50/LC50: CAS# 1327-53-3: Oral, mouse: LD50 = 20 mg/kg; Oral, rabbit: LD50 = 20190 ug/kg; Oral, rat: LD50 = 10 mg/kg; .Carcinogenicity: CAS# 1327-53-3: ACGIH: A1 - Confirmed Human Carcinogen (listed as 'Arsenic').A1 - Confirmed Human Carcinogen (listed as 'Arsenic, inorganic compounds'). California: carcinogen, initial date 2/27/87 (listed as Arsenic, inorganic compounds). NTP: Known carcinogen (listed as Arsenic, inorganic compounds). IARC: Group 1 carcinogen (listed as Arsenic). Epidemiology: In a large number of studies, exposure to inorganic arsenic compounds in drugs, food, and water as well as in an occupational setting have been causally associated with the developmental of cancer, primarily of the skin and lungs. Teratogenicity: Teratogenic effects, including exencephaly, skeletal defects, and genitourinay system defects, of arsenic compounds administered intravenously or intraperitoneally t high doses have been demonstrated in hamsters, rats and mice. Reproductive Effects: May cause reproductive effects. Mutagenicity: No information available. Neurotoxicity: No information available. Other Studies:

Section 12 - Ecological Information

Ecotoxicity: Water flea Daphnia: LC50 = 0.038 mg/L; 24 Hr.; UnspecifiedBacteria: Phytobacterium phosphoreum: EC50 = 31.43-73.73 mg/L; 5,15,30 minutes; Microtox test No data available. Environmental: Terrestrial: Half-life in soil 6.5 years. Aquatic: Tends to bioaccumulate. Will biodegrade to arsine and will bioconcentrate. Physical: No information available. Other: No information available.

123

Appendix B (Continued)

Section 13 - Disposal Considerations

Chemical waste generators must determine whether a discarded chemical is classified as a hazardous waste. US EPA guidelines for the classification determination are listed in 40 CFR Parts 261.3. Additionally, waste generators must consult state and local hazardous waste regulations to ensure complete and accurate classification. RCRA P-Series: CAS# 1327-53-3: waste number P012. RCRA U-Series: None listed.

Section 14 - Transport Information

US DOT Canada TDG

Shipping Name:

DOT regulated - small quantity provisions apply (see 49CFR173.4)

No information available.

Hazard Class: UN Number: Packing Group:

Section 15 - Regulatory Information

US FEDERAL TSCA CAS# 1327-53-3 is listed on the TSCA inventory. Health & Safety Reporting List None of the chemicals are on the Health & Safety Reporting List. Chemical Test Rules None of the chemicals in this product are under a Chemical Test Rule. Section 12b None of the chemicals are listed under TSCA Section 12b. TSCA Significant New Use Rule None of the chemicals in this material have a SNUR under TSCA. CERCLA Hazardous Substances and corresponding RQs CAS# 1327-53-3: 1 lb final RQ; 0.454 kg final RQ

124

Appendix B (Continued) SARA Section 302 Extremely Hazardous Substances CAS# 1327-53-3: 100 lb TPQ (lower threshold); 10000 lb TPQ (upper thre shold) SARA Codes CAS # 1327-53-3: immediate, delayed. Section 313 This material contains Arsenic trioxide (listed as Arsenic), 99.999%, (CAS# 1327-53-3) which is subject to the reporting requirements of Section 313 of SARA Title III and 40 CFR Part 373. Clean Air Act: CAS# 1327-53-3 (listed as Arsenic, inorganic compounds) is listed as a hazardous air pollutant (HAP). This material does not contain any Class 1 Ozone depletors. This material does not contain any Class 2 Ozone depletors. Clean Water Act: CAS# 1327-53-3 is listed as a Hazardous Substance under the CWA. CAS# 1327-53-3 is listed as a Priority Pollutant under the Clean Water Act. CAS# 1327-53-3 is listed as a Toxic Pollutant under the Clean Water Act. OSHA: None of the chemicals in this product are considered highly hazardous by OSHA. STATE CAS# 1327-53-3 can be found on the following state right to know lists: California, New Jersey, Pennsylvania, Minnesota, (listed as Arsenic), Minnesota, (listed as Arsenic, inorganic compounds), Massachusetts. California Prop 65 The following statement(s) is(are) made in order to comply with the California Safe Drinking Water Act: WARNING: This product contains Arsenic trioxide, listed as `Arsenic, inorganic compounds', a chemical known to the state of California to cause cancer. WARNING: This product contains Arsenic trioxide, listed as `Arsenic (inorganic oxides)', a chemical known to the state of California to cause developmental reproductive toxicity. California No Significant Risk Level: CAS# 1327-53-3: 0.06 æg/day NSRL (inhalation); 10 æg/day NSRL (except inhalation) (listed under Arsenic) European/International Regulations European Labeling in Accordance with EC Directives Hazard Symbols: T+ N

125

Appendix B (Continued) Risk Phrases: R 28 Very toxic if swallowed. R 34 Causes burns. R 45 May cause cancer. R 50/53 Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment. Safety Phrases: S 45 In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible). S 53 Avoid exposure - obtain special instructions before use. S 60 This material and its container must be disposed of as hazardou s waste. S 61 Avoid release to the environment. Refer to special instructions /safety data sheets. WGK (Water Danger/Protection) CAS# 1327-53-3: 3 Canada - DSL/NDSL CAS# 1327-53-3 is listed on Canada's DSL List. Canada - WHMIS not available. This product has been classified in accordance with the hazard criteria of the Controlled Products Regulations and the MSDS contains all of the information required by those regulations. Canadian Ingredient Disclosure List CAS# 1327-53-3 is listed on the Canadian Ingredient Disclosure List.

Section 16 - Additional Information

MSDS Creation Date: 6/21/1999 Revision #5 Date: 10/03/2005 The information above is believed to be accurate and represents the best information currently available to us. However, we make no warranty of merchantability or any other warranty, express or implied, with respect to such information, and we assume no liability resulting from its use. Users should make their own investigations to determine the suitability of the information for their particular purposes. In no event shall Fisher be liable for any claims, losses, or damages of any third party or for lost profits or any special, indirect, incidental, consequential or exemplary damages, howsoever arising, even if Fisher has been advised of the possibility of such damages.

126

Appendix B (Continued)

B.3. Arsenic (V) Oxide Material Safety Data Sheet Arsenic(V) oxide ACC# 02088

Section 1 - Chemical Product and Company Identification

MSDS Name: Arsenic(V) oxide Catalog Numbers: AC192500000, AC192500250, AC366310000, AC366310050, AC366310250 Synonyms: Arsenic pentoxide; Diarsenic pentaoxide; Arsenic acid anhydride; Arsenic anhydride. Company Identification: Acros Organics N.V. One Reagent Lane Fair Lawn, NJ 07410 For information in North America, call: 800-ACROS-01 For emergencies in the US, call CHEMTREC: 800-424-9300

Section 2 - Composition, Information on Ingredients

CAS# Chemical Name Percent EINECS/ELINCS1303-28-2 Arsenic(V) oxide >99.9 215-116-9

Section 3 - Hazards Identification

EMERGENCY OVERVIEW Appearance: white solid. Danger! May be fatal if swallowed. Cancer hazard. Contains inorganic arsenic. Harmful if inhaled. Causes eye, skin, and respiratory tract irritation. May cause nervous system effects. May cause fetal effects. Target Organs: Liver, lungs, nervous system, skin. Potential Health Effects Eye: May cause eye irritation. May result in corneal injury. Skin: May cause skin irritation. May cause skin sensitization, an allergic reaction, which becomes evident upon re-exposure to this material.

127

Appendix B (Continued) Ingestion: May cause liver damage. Can cause nervous system damage. Ingestion of arsenical compounds may cause burning of the lips, throat constriction, swallowing difficulties, severe abdominal pain, severe nausea, projectile vomiting, and profuse diarrhea. All soluble arsenic (As) compounds are considered to be poisonous to humans. Inorganic arsenic is more toxic than organic arsenic. Organic arsenic is excreted more rapidly than inorganic arsenic. Arsenic 5+ is excreted more rapidly than arsenic 3+. Arsenic inhibits enzymes required for cellular respiration and also competes with phosphorus for incorporation into ATP, depleting cellular energy stores and leading to cell death. Inhalation: Causes respiratory tract irritation. May cause effects similar to those described for ingestion. Inhalation of arsenic compounds may lead to irritation of the respiratory tract and to possible nasal perforation. Chronic: Chronic ingestion is characterized by weakness, anorexia, gastrointestinal disturbances, impairment of cognitive function, peripheral neuropathy, and skin disorders. Chronic ingestion may cause fetal effects. Inorganic arsenic compounds may cause skin and lung cancers in humans. Based on a case report of one family with chronic exposure, the spectrum of toxic effects from arsenic pentoxide may include skin rashes, nosebleeds, easy bruising, hair loss, headaches, malaise, and grand mal seizures. Because of mixed exposures, these eeffects cannot be attributed solely to arsenic pentoxide.

Section 4 - First Aid Measures

Eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately. Skin: Flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Get medical aid if irritation develops or persists. Ingestion: Call a poison control center. If swallowed, do not induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an unconscious person. Get medical aid. Inhalation: Get medical aid immediately. Remove from exposure and move to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Notes to Physician: Treat symptomatically and supportively.

128

Appendix B (Continued))

Section 5 - Fire Fighting Measures

General Information: As in any fire, wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Extinguishing Media: Use water spray to cool fire-exposed containers. Flash Point: Not available. Autoignition Temperature: Not available. Explosion Limits, Lower:Not available. Upper: Not available. NFPA Rating: (estimated) Health: 3; Flammability: 0; Instability: 0

Section 6 - Accidental Release Measures

General Information: Use proper personal protective equipment as indicated in Section 8. Spills/Leaks: Vacuum or sweep up material and place into a suitable disposal container. Avoid generating dusty conditions. Provide ventilation.

Section 7 - Handling and Storage

Handling: Wash thoroughly after handling. Remove contaminated clothing and wash before reuse. Do not get in eyes, on skin, or on clothing. Do not ingest or inhale. Use only with adequate ventilation or respiratory protection. Storage: Poison room locked.

Section 8 - Exposure Controls, Personal Protection

Engineering Controls: Use adequate general or local exhaust ventilation to keep airborne concentrations below the permissible exposure limits. See 29CFR 1910.1018 for regulatory requirements pertaining to all occupational exposures to inorganic arsenic.

129

Appendix B (Continued) Exposure Limits

Chemical Name ACGIH NIOSH OSHA - Final PELs

Arsenic(V) oxide

0.01 mg/m3 TWA (as As) (listed under Arsenic, inorganic compounds).

5 mg/m3 IDLH (as As) (listed under Arsenic, inorganic compounds).

5 æg/m3 Action Level (as As); 10 æg/m3 PEL (as As. Cancer hazard - see 29 CFR 1 910.1018. Arsine excepted) (listed under Arsenic, inorganic compounds).

OSHA Vacated PELs: Arsenic(V) oxide: No OSHA Vacated PELs are listed for this chemical. Personal Protective Equipment Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure. Respirators: Follow the OSHA respirator regulations found in 29 CFR 1910.134 or European Standard EN 149. Use a NIOSH/MSHA or European Standard EN 149 approved respirator if exposure limits are exceeded or if irritation or other symptoms are experienced.

Section 9 - Physical and Chemical Properties

Physical State: Solid Appearance: white Odor: odorless pH: acidic in soln Vapor Pressure: Not available. Vapor Density: Not available. Evaporation Rate:Not available. Viscosity: Not available. Boiling Point: Not available. Freezing/Melting Point:315 deg C (dec) Decomposition Temperature:315 deg C Solubility: Soluble.

130

Appendix B (Continued) Specific Gravity/Density:Not available. Molecular Formula:As2O5 Molecular Weight:229.84

Section 10 - Stability and Reactivity

Chemical Stability: Stable under normal temperatures and pressures. Conditions to Avoid: Excess heat, moist air. Incompatibilities with Other Materials: Acids, aluminum, halogens, zinc, rubidium carbide. Hazardous Decomposition Products: Oxides of arsenic. Hazardous Polymerization: Has not been reported.

Section 11 - Toxicological Information

RTECS#: CAS# 1303-28-2: CG2275000 LD50/LC50: CAS# 1303-28-2: Oral, mouse: LD50 = 55 mg/kg; Oral, rat: LD50 = 8 mg/kg; . Carcinogenicity: CAS# 1303-28-2: ACGIH: A1 - Confirmed Human Carcinogen (listed as 'Arsenic, inorganic compounds'). California: carcinogen, initial date 2/27/87 (listed as Arsenic, inorganic compounds). NTP: Known carcinogen (listed as Arsenic, inorganic compounds). IARC: Group 1 carcinogen (listed as Arsenic compounds, n.o.s.). Epidemiology: No data available. Teratogenicity: No data available. Reproductive Effects: No data available. Mutagenicity: No data available. Neurotoxicity: No data available.

131

Appendix B (Continued) Other Studies:

Section 12 - Ecological Information

Ecotoxicity: No data available. No information available. Environmental: No information available. Physical: No information available. Other: Used in wood preservatives, weed control, and as fungicide.

Section 13 - Disposal Considerations

Chemical waste generators must determine whether a discarded chemical is classified as a hazardous waste. US EPA guidelines for the classification determination are listed in 40 CFR Parts 261.3. Additionally, waste generators must consult state and local hazardous waste regulations to ensure complete and accurate classification. RCRA P-Series: CAS# 1303-28-2: waste number P011. RCRA U-Series: None listed.

Section 14 - Transport Information

US DOT Canada TDG

Shipping Name:

DOT regulated - small quantity provisions apply (see 49CFR173.4)

ARSENIC PENTOXIDE

Hazard Class: 6.1 UN Number: UN1559 Packing Group: II

Section 15 - Regulatory Information

US FEDERAL TSCA CAS# 1303-28-2 is listed on the TSCA inventory. Health & Safety Reporting List None of the chemicals are on the Health & Safety Reporting List.

132

Appendix B (Continued) Chemical Test Rules None of the chemicals in this product are under a Chemical Test Rule. Section 12b None of the chemicals are listed under TSCA Section 12b. TSCA Significant New Use Rule None of the chemicals in this material have a SNUR under TSCA. CERCLA Hazardous Substances and corresponding RQs CAS# 1303-28-2: 1 lb final RQ; 0.454 kg final RQ SARA Section 302 Extremely Hazardous Substances CAS# 1303-28-2: 100 lb TPQ (lower threshold); 10000 lb TPQ (upper thre shold) Section 313 This material contains Arsenic(V) oxide (listed as Arsenic, inorganic compounds), >99.9%, (CAS# 1303-28-2) which is subject to the reporting requirements of Section 313 of SARA Title III and 40 CFR Part 373. Clean Air Act: CAS# 1303-28-2 (listed as Arsenic, inorganic compounds) is listed as a hazardous air pollutant (HAP). This material does not contain any Class 1 Ozone depletors. This material does not contain any Class 2 Ozone depletors. Clean Water Act: CAS# 1303-28-2 is listed as a Hazardous Substance under the CWA. None of the chemicals in this product are listed as Priority Pollutants under the CWA. CAS# 1303-28-2 is listed as a Toxic Pollutant under the Clean Water Act. OSHA: None of the chemicals in this product are considered highly hazardous by OSHA. STATE CAS# 1303-28-2 can be found on the following state right to know lists: California, New Jersey, Pennsylvania, Minnesota, (listed as Arsenic, inorganic compounds), Massachusetts. California Prop 65 The following statement(s) is(are) made in order to comply with the California Safe Drinking Water Act: WARNING: This product contains Arsenic(V) oxide, listed as `Arsenic, inorganic compounds', a chemical known to the state of California to cause cancer. WARNING: This product contains Arsenic(V) oxide, listed as `Arsenic (inorganic oxides)', a chemical known to the state of California to cause developmental reproductive toxicity.

133

Appendix B (Continued) California No Significant Risk Level: None of the chemicals in this product are listed. European/International Regulations European Labeling in Accordance with EC Directives Hazard Symbols: T N Risk Phrases: R 23/25 Toxic by inhalation and if swallowed. R 45 May cause cancer. R 50/53 Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment. Safety Phrases: S 45 In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible). S 53 Avoid exposure - obtain special instructions before use. S 60 This material and its container must be disposed of as hazardou s waste. S 61 Avoid release to the environment. Refer to special instructions /safety data sheets. WGK (Water Danger/Protection) CAS# 1303-28-2: 3 Canada - DSL/NDSL CAS# 1303-28-2 is listed on Canada's DSL List. Canada - WHMIS This product has a WHMIS classification of D2A, D1A. This product has been classified in accordance with the hazard criteria of the Controlled Products Regulations and the MSDS contains all of the information required by those regulations. Canadian Ingredient Disclosure List CAS# 1303-28-2 is listed on the Canadian Ingredient Disclosure List.

134

Appendix B (Continued)

Section 16 - Additional Information

MSDS Creation Date: 9/02/1997 Revision #4 Date: 6/01/2005 The information above is believed to be accurate and represents the best information currently available to us. However, we make no warranty of merchantability or any other warranty, express or implied, with respect to such information, and we assume no liability resulting from its use. Users should make their own investigations to determine the suitability of the information for their particular purposes. In no event shall Fisher be liable for any claims, losses, or damages of any third party or for lost profits or any special, indirect, incidental, consequential or exemplary damages, howsoever arising, even if Fisher has been advised of the possibility of such damages.

135

Appendix B (Continued)

B.4. Arsenic Standard Solution MATERIAL SAFETY DATA SHEET ______________________________________ 1. CHEMICAL PRODUCT AND COMPANY IDENTIFICATION Product Name: Arsenic Reference Standard Solution 1000 ± 10 mg/l as As+3 Catalog Number: 1457142 Hach Company Emergency Telephone Numbers: P.O.Box 389 (Medical and Transportation) Loveland, CO USA 80539 (303) 623-5716 24 Hour Service (970) 669-3050 (515)232-2533 8am - 4pm CST MSDS Number: M00697 Chemical Name: Not applicable CAS No.: Not applicable Chemical Formula: Not applicable Chemical Family: Not applicable Hazard: Carcinogen. Harmful if swallowed Date of MSDS Preparation: Day: 23 Month: 09 Year: 2004 ______________________________________ 2. COMPOSITION / INFORMATION ON INGREDIENTS Sodium Hydroxide CAS No.: 1310-73-2 TSCA CAS Number: 1310-73-2 Percent Range: < 0.1 Percent Range Units: weight / volume LD50: Oral rat LDLo = 500 mg/kg. LC50: None reported TLV: 2 mg/m³ PEL: 2 mg/m³ Hazard: Causes severe burns. Toxic. Demineralized Water CAS No.: 7732-18-5 TSCA CAS Number: 7732-18-5 Percent Range: > 99.0 Percent Range Units: volume / volume LD50: None reported LC50: None reported TLV: Not established PEL: Not established

136

Appendix B (Continued) Hazard: No effects anticipated. Arsenic Trioxide CAS No.: 1327-53-3 TSCA CAS Number: 1327-53-3 Percent Range: < 0.5 Percent Range Units: weight / volume LD50: Oral rat LD50 = 15.1 mg/kg; Oral human LDLo = 29 mg/kg LC50: None reported TLV: 0.2 mg/m3 as As PEL: 0.01 mg/m3 as As Hazard: Poison. Carcinogen. May cause irritation. ______________________________________ 3. HAZARDS IDENTIFICATION Emergency Overview: Appearance: Clear, colorless liquid Odor: None HARMFUL IF SWALLOWED CANCER HAZARD CONTAINS MATERIAL WHICH CAN CAUSE CANCER HMIS: Health: 4 Flammability: 0 Reactivity: 0 Protective Equipment: X - See protective equipment, Section 8. NFPA: Health: 2 Flammability: 0 Reactivity: 0 Symbol: Not applicable Potential Health Effects: Eye Contact: May cause irritiation Skin Contact: No effects are anticipated Skin Absorption: Will be absorbed through the skin. Effects similar to those of ingestion Target Organs: Blood Liver Kidneys Central nervous system Ingestion: Can cause: nausea vomiting gastrointestinal irritation convulsions death Target Organs: Blood Liver Kidneys Central nervous system Inhalation: No data reported. Target Organs: None reported Medical Conditions Aggravated: Pre-existing: Liver conditions Kidney conditions blood disorders

137

Appendix B (Continued) Chronic Effects: Chronic overexposure may cause central nervous system effects gastrointestinal disturbances kidney damage liver damage muscle aches death Cancer / Reproductive Toxicity Information: An ingredient of this product is an OSHA listed carcinogen. Inorganic Arsenic An ingredient of this mixture is: IARC Group 1: Recognized Carcinogen Inorganic Arsenic An ingredient of this mixture is: NTP Listed Group 1: Recognized Carcinogen Inorganic Arsenic Additional Cancer / Reproductive Toxicity Information: Contains: an experimental mutagen. an experimental teratogen. Toxicologically Synergistic Products: None reported ______________________________________ 4. FIRST AID Eye Contact: Immediately flush eyes with water for 15 minutes. Call physician. Skin Contact (First Aid): Wash skin with plenty of water. Call physician if irritation develops. Ingestion (First Aid): Induce vomiting using syrup of ipecac or by sticking finger down throat. Never give anything by mouth to an unconscious person. Call physician immediately. Inhalation: None required. ______________________________________ 5. FIRE FIGHTING MEASURES Flammable Properties: Material will not burn. Flash Point: Not applicable Method: Not applicable Flammability Limits: Lower Explosion Limits: Not applicable Upper Explosion Limits: Not applicable Autoignition Temperature: Not applicable Hazardous Combustion Products: Not applicable Fire / Explosion Hazards: None reported Static Discharge: None reported. Mechanical Impact: None reported Extinguishing Media: Use media appropriate to surrounding fire conditions Fire Fighting Instruction: As in any fire, wear self-contained breathing apparatus pressure-demand and full protective gear.

138

Appendix B (Continued) ______________________________________ 6. ACCIDENTAL RELEASE MEASURES Spill Response Notice: Only persons properly qualified to respond to an emergency involving hazardous substances may respond to a spill according to federal regulations (OSHA 29 CFR 1910.120(a)(v)) and per your company's emergency response plan and guidelines/procedures. See Section 13, Special Instructions for disposal assistance. Containment Technique: Releases of this material may contaminate the environment. Absorb spilled liquid with nonreactive sorbent material. Stop spilled material from being released to the environment. Dike the spill to contain material for later disposal. Clean-up Technique: Avoid contact with spilled material. Absorb spilled liquid with non-reactive sorbent material. Sweep up material. Dispose of material in an E.P.A. approved hazardous waste facility. Decontaminate the area of the spill with a soap solution. Evacuation Procedure: Evacuate general area (50 foot radius or as directed by your facility's emergency response plan) when: any quantity is spilled. If conditions warrant, increase the size of the evacuation. Special Instructions (for accidental release): Mixture contains a component which is regulated as a water pollutant. Mixture contains a component which is regulated as a hazardous air pollutant. 304 EHS RQ (40 CFR 355): Arsenic Trioxide - RQ 1 lbs D.O.T. Emergency Response Guide Number: None ______________________________________ 7. HANDLING / STORAGE Handling: Avoid contact with eyes skin Do not breathe mist or vapors. Wash thoroughly after handling. Maintain general industrial hygiene practices when using this product. Storage: Keep container tightly closed when not in use. Flammability Class: Not applicable ______________________________________ 8. EXPOSURE CONTROLS / PROTECTIVE EQUIPMENT Engineering Controls: Have an eyewash station nearby. Maintain general industrial hygiene practices when using this product. Personal Protective Equipment:

139

Appendix B (Continued) Eye Protection: safety glasses with top and side shields Skin Protection: lab coat disposable latex gloves Inhalation Protection: adequate ventilation Precautionary Measures: Avoid contact with: eyes skin Do not breathe: mist/vapor Wash thoroughly after handling. TLV: Not established PEL: Not established ______________________________________ 9. PHYSICAL / CHEMICAL PROPERTIES Appearance: Clear, colorless liquid Physical State: Liquid Molecular Weight: Not applicable Odor: None pH: 5-7 Vapor Pressure: Not determined Vapor Density (air = 1): Not determined Boiling Point: 100°C Melting Point: Not determined Specific Gravity (water = 1): 0.997 Evaporation Rate (water = 1): 1.053 Volatile Organic Compounds Content: Not applicable Partition Coefficient (n-octanol / water): Not applicable Solubility: Water: Soluble Acid: Soluble Other: Not determined Metal Corrosivity: Steel: Not determined Aluminum: Not determined ______________________________________ 10. STABILITY / REACTIVITY Chemical Stability: Stable when stored under proper conditions. Conditions to Avoid: Heating to decomposition. Extreme temperatures Evaporation Reactivity / Incompatibility: None reported Hazardous Decomposition: Heating to decomposition releases: arsine Hazardous Polymerization: Will not occur. ______________________________________ 11. TOXICOLOGICAL INFORMATION Product Toxicological Data: LD50: None reported LC50: None reported

140

Appendix B (Continued) Dermal Toxicity Data: None reported Skin and Eye Irritation Data: None reported Mutation Data: Arsenic Trioxide: Human lung - Unscheduled DNA synthesis - 1µmol/l; Human lymphocyte - sister chromatid exchange - 2µg/cm3 Reproductive Effects Data: Oral Mouse TDLo = 3636 mg/kg : Reproductive - Fertility - abortion Ingredient Toxicological Data: Arsenic Trioxide: Oral rat LD50 = 15.1 mg/kg; Oral human LDLo = 29 mg/kg ______________________________________ 12. ECOLOGICAL INFORMATION Product Ecological Information: -- No ecological data available for this product. Ingredient Ecological Information: -- No ecological data available for the ingredients of this product. ______________________________________ 13. DISPOSAL CONSIDERATIONS EPA Waste ID Number: D004 Special Instructions (Disposal): Dispose of material in an E.P.A. approved hazardous waste facility. Empty Containers: Rinse three times with an appropriate solvent. Dispose of empty container as normal trash. NOTICE (Disposal): These disposal guidelines are based on federal regulations and may be superseded by more stringent state or local requirements. Please consult your local environmental regulators for more information. _____________________________________ 14. TRANSPORT INFORMATION D.O.T.: D.O.T. Proper Shipping Name: Not Currently Regulated -- DOT Hazard Class: NA DOT Subsidiary Risk: NA DOT ID Number: NA DOT Packing Group: NA I.C.A.O.: I.C.A.O. Proper Shipping Name: Not Currently Regulated -- ICAO Hazard Class: NA ICAO Subsidiary Risk: NA ICAO ID Number: NA ICAO Packing Group: NA I.M.O.:

141

Appendix B (Continued) I.M.O. Proper Shipping Name: Not Currently Regulated I.M.O. Hazard Class: NA I.M.O. Subsidiary Risk: NA I.M.O. ID Number: NA I.M.O. Packing Group: NA Additional Information: This product may be shipped as part of a chemical kit composed of various compatible dangerous goods for analytical or testing purposes. This kit would have the following classification: Proper Shipping Name: Chemical Kit Hazard Class: 9 UN Number 3316 ______________________________________ 15. REGULATORY INFORMATION U.S. Federal Regulations: O.S.H.A.: This product contains Inorganic arsenic and is regulated under 29CFR Subpart Z 1910.1018. E.P.A.: S.A.R.A. Title III Section 311/312 Categorization (40 CFR 370): Immediate (Acute) Health Hazard Delayed (Chronic) Health Hazard S.A.R.A. Title III Section 313 (40 CFR 372): This product contains a chemical(s) subject to the reporting requirements of Section 313 of Title III of SARA. Arsenic Trioxide 302 (EHS) TPQ (40 CFR 355): Arsenic Trioxide 100 lbs. 304 CERCLA RQ (40 CFR 302.4): Arsenic Trioxide 1 lb. 304 EHS RQ (40 CFR 355): Arsenic Trioxide - RQ 1 lbs Clean Water Act (40 CFR 116.4): Arsenic trioxide - RQ 1 lb. RCRA: Contains RCRA regulated substances. See Section 13, EPA Waste ID Number. C.P.S.C.: Not applicable State Regulations: California Prop. 65: WARNING - This product contains a chemical known to the State of California to cause cancer. Identification of Prop. 65 Ingredient(s): Arsenic (inorganic compounds) Trade Secret Registry: Not applicable National Inventories: U.S. Inventory Status: All ingredients in this product are listed on the TSCA 8(b) Inventory (40 CFR 710). TSCA CAS Number: Not applicable

142

Appendix B (Continued) ______________________________________ 16. OTHER INFORMATION Intended Use: Standard solution References: 29 CFR 1900 - 1910 (Code of Federal Regulations - Labor). Air Contaminants, Federal Register, Vol. 54, No. 12. Thursday, January 19, 1989. pp. 2332-2983. TLV's Threshold Limit Values and Biological Exposure Indices for 1992-1993. American Conference of Governmental Industrial Hygienists, 1992. Technical Judgment. IARC Monographs on the Evaluation of the Carcinogenic Risks to Humans. World Health Organization (Volumes 1-42) Supplement 7. France: 1987. In-house information. Fire Protection Guide on Hazardous Materials, 10th Ed. Quincy, MA: National Fire Protection Fire Protection Guide on Hazardous Materials, 10th Ed. Quincy, MA: National Fire Protection Association, 1991. List of Dangerous Substances Classified in Annex I of the EEC Directive (67/548) - Classification, Packaging and Labeling of Dangerous Substances, Amended July 1992. Revision Summary: Updates in Section(s) 14, _______________________________________ Legend: NA - Not Applicable w/w - weight/weight ND - Not Determined w/v - weight/volume NV - Not Available v/v - volume/volume USER RESPONSIBILITY: Each user should read and understand this information and incorporate it in individual site safety programs in accordance with applicable hazard communication standards and regulations. THE INFORMATION CONTAINED HEREIN IS BASED ON DATA CONSIDERED TO BE ACCURATE. HOWEVER, NO WARRANTY IS EXPRESSED OR IMPLIED REGARDING THE ACCURACY OF THESE DATA OR THE RESULTS TO BE OBTAINED FROM THE USE THEREOF. HACH COMPANY ©2004

143

Appendix B (Continued)

B.5. Kaolin Material Safety Data Sheet Kaolin, acid washed powder, USP ACC# 12325

Section 1 - Chemical Product and Company Identification

MSDS Name: Kaolin, acid washed powder, USP Catalog Numbers: K2-500, K2-500LOT001 Synonyms: Aluminum silicate (hydrated); Bolus Alba; China clay; Porcelain clay; White Bole. Company Identification: Fisher Scientific 1 Reagent Lane Fair Lawn, NJ 07410 For information, call: 201-796-7100 Emergency Number: 201-796-7100 For CHEMTREC assistance, call: 800-424-9300 For International CHEMTREC assistance, call: 703-527-3887

Section 2 - Composition, Information on Ingredients

CAS# Chemical Name Percent EINECS/ELINCS1332-58-7 Kaolin 100 unlisted

Section 3 - Hazards Identification

EMERGENCY OVERVIEW Appearance: white to yellow solid. Caution! May cause eye, skin, and respiratory tract irritation. This is expected to be a low hazard for usual industrial handling. Target Organs: None. Potential Health Effects Eye: Dust may cause mechanical irritation. Skin: Dust may cause mechanical irritation. Ingestion: Ingestion of large amounts may cause gastrointestinal irritation. Low hazard for usual industrial handling. Inhalation: May cause respiratory tract irritation. Low hazard for usual industrial

144

Appendix B (Continued) handling. When inhaled as a dust or fume, may cause benign pneumoconiosis. Chronic: Chronic inhalation can cause pneumoconiosis.

Section 4 - First Aid Measures

Eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. If irritation develops, get medi cal aid. Skin: Flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Get medical aid if irritation develops or persists. Wash clothing before reuse. Ingestion: Never give anything by mouth to an unconscious person. Do NOT induce vomiting. If conscious and alert, rinse mouth and drink 2-4 cupfuls of milk or water. Wash mouth out with water. Get medical aid if irritation or symptoms occur. Inhalation: Remove from exposure and move to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid if cough or other symptoms appear. Notes to Physician: Treat symptomatically and supportively.

Section 5 - Fire Fighting Measures

General Information: As in any fire, wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Substance is noncombustible. Extinguishing Media: Use extinguishing media most appropriate for the surrounding fire. Flash Point: Not applicable. Autoignition Temperature: Not applicable. Explosion Limits, Lower:Not available. Upper: Not available. NFPA Rating: (estimated) Health: 1; Flammability: 0; Instability: 0

Section 6 - Accidental Release Measures

General Information: Use proper personal protective equipment as indicated in Section 8. Spills/Leaks: Vacuum or sweep up material and place into a suitable disposal container. Clean up spills immediately, observing precautions in the Protective Equipment section. Avoid generating dusty conditions. Provide ventilation.

145

Appendix B (Continued)

Section 7 - Handling and Storage

Handling: Wash thoroughly after handling. Wash hands before eating. Use with adequate ventilation. Minimize dust generation and accumulation. Avoid contact with eyes, skin, and clothing. Keep container tightly closed. Avoid breathing dust. Storage: Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances. No special precautions indicated.

Section 8 - Exposure Controls, Personal Protection

Engineering Controls: Use adequate general or local exhaust ventilation to keep airborne concentrations below the permissible exposure limits. Exposure Limits

Chemical Name ACGIH NIOSH OSHA - Final PELs

Kaolin

2 mg/m3 TWA (respirable fraction, particulate matter containing no asbestos and < 1% crystalline silica)

10 mg/m3 TWA (total dust); 5 mg/m3 TWA (respirable dust)3000 mg/m3 IDLH (listed under Silica, amorphous).

15 mg/m3 TWA (total dust); 5 mg/m3 TWA (respirable fraction)

OSHA Vacated PELs: Kaolin: 10 mg/m3 TWA (total dust); 5 mg/m3 TWA (respirable fraction) Personal Protective Equipment Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to minimize contact with skin. Respirators: Follow the OSHA respirator regulations found in 29 CFR 1910.134 or European Standard EN 149. Use a NIOSH/MSHA or European Standard EN 149 approved respirator if exposure limits are exceeded or if irritation or other symptoms are experienced.

146

Appendix B (Continued)

Section 9 - Physical and Chemical Properties

Physical State: Solid Appearance: white to yellow Odor: none reported pH: Not available. Vapor Pressure: Negligible. Vapor Density: Not available. Evaporation Rate:Not applicable. Viscosity: Not available. Boiling Point: Not available. Freezing/Melting Point:3200 deg F Decomposition Temperature:Not available. Solubility: Insoluble in water. Specific Gravity/Density:1.8 to 2.6 Molecular Formula:H2Al2Si2O8-H2O Molecular Weight:258.2

Section 10 - Stability and Reactivity

Chemical Stability: Stable under normal temperatures and pressures. Conditions to Avoid: Dust generation, excess heat. Incompatibilities with Other Materials: Strong acids, strong bases. Hazardous Decomposition Products: Silicon dioxide, aluminum oxide. Hazardous Polymerization: Has not been reported.

Section 11 - Toxicological Information

RTECS#: CAS# 1332-58-7: GF1670500 LD50/LC50: Not available. Carcinogenicity: CAS# 1332-58-7: Not listed by ACGIH, IARC, NTP, or CA Prop 65. Epidemiology: No information available. Teratogenicity: No information available. Reproductive Effects: No information available.

147

Appendix B (Continued) Mutagenicity: No information available. Neurotoxicity: No information available. Other Studies:

Section 12 - Ecological Information

No information available.

Section 13 - Disposal Considerations

Chemical waste generators must determine whether a discarded chemical is classified as a hazardous waste. US EPA guidelines for the classification determination are listed in 40 CFR Parts 261.3. Additionally, waste generators must consult state and local hazardous waste regulations to ensure complete and accurate classification. RCRA P-Series: None listed. RCRA U-Series: None listed.

Section 14 - Transport Information

US DOT Canada TDG Shipping Name:

Not regulated as a hazardous material No information available.

Hazard Class: UN Number: Packing Group:

Section 15 - Regulatory Information

US FEDERAL TSCA CAS# 1332-58-7 is listed on the TSCA inventory. Health & Safety Reporting List None of the chemicals are on the Health & Safety Reporting List. Chemical Test Rules None of the chemicals in this product are under a Chemical Test Rule. Section 12b None of the chemicals are listed under TSCA Section 12b.

148

Appendix B (Continued) TSCA Significant New Use Rule None of the chemicals in this material have a SNUR under TSCA. CERCLA Hazardous Substances and corresponding RQs None of the chemicals in this material have an RQ. SARA Section 302 Extremely Hazardous Substances None of the chemicals in this product have a TPQ. Section 313 No chemicals are reportable under Section 313. Clean Air Act: This material does not contain any hazardous air pollutants. This material does not contain any Class 1 Ozone depletors. This material does not contain any Class 2 Ozone depletors. Clean Water Act: None of the chemicals in this product are listed as Hazardous Substances under the CWA. None of the chemicals in this product are listed as Priority Pollutants under the CWA. None of the chemicals in this product are listed as Toxic Pollutants under the CWA. OSHA: None of the chemicals in this product are considered highly hazardous by OSHA. STATE CAS# 1332-58-7 can be found on the following state right to know lists: California, (listed as Silica, amorphous), New Jersey, (listed as Silica, amorphous), Pennsylvania, Minnesota, Massachusetts. California Prop 65 California No Significant Risk Level: None of the chemicals in this product are listed. European/International Regulations European Labeling in Accordance with EC Directives Hazard Symbols: Not available. Risk Phrases:

149

Appendix B (Continued) Safety Phrases: S 24/25 Avoid contact with skin and eyes. S 37 Wear suitable gloves. S 45 In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible). S 28A After contact with skin, wash immediately with plenty of water WGK (Water Danger/Protection) CAS# 1332-58-7: 0 Canada - DSL/NDSL CAS# 1332-58-7 is listed on Canada's DSL List. Canada - WHMIS This product has a WHMIS classification of Not controlled.. This product has been classified in accordance with the hazard criteria of the Controlled Products Regulations and the MSDS contains all of the information required by those regulations. Canadian Ingredient Disclosure List CAS# 1332-58-7 (listed as Silica, amorphous) is listed on the Canadian Ingredient Disclosure List.

Section 16 - Additional Information

MSDS Creation Date: 2/16/1999 Revision #4 Date: 10/03/2005 The information above is believed to be accurate and represents the best information currently available to us. However, we make no warranty of merchantability or any other warranty, express or implied, with respect to such information, and we assume no liability resulting from its use. Users should make their own investigations to determine the suitability of the information for their particular purposes. In no event shall Fisher be liable for any claims, losses, or damages of any third party or for lost profits or any special, indirect, incidental, consequential or exemplary damages

Appendix B (Continued)

B.6. Nickel Nitrate

NICKEL NITRATE

1. Product Identification Synonyms: Nickel (II) nitrate, hexahydrate (1:2:6); nickelous nitrate; nitric acid, nickel (2+) salt, hexahydrate; Nickelous nitrate, 6- Hydrate CAS No.: 13138-45-9 Anhydrous; (13478-00-7 Hexahydrate) Molecular Weight: 290.83 Chemical Formula: Ni(NO3)2 6H2O Product Codes: J.T. Baker: 2784 Mallinckrodt: 6384

2. Composition/Information on Ingredients Ingredient CAS No Percent Hazardous --------------------------------------- ------------ ------------ --------- Nickel Nitrate 13138-45-9 90 - 100% Yes

3. Hazards Identification Emergency Overview -------------------------- DANGER! STRONG OXIDIZER. CONTACT WITH OTHER MATERIAL MAY CAUSE FIRE. HARMFUL IF SWALLOWED OR INHALED. CAUSES IRRITATION TO SKIN, EYES AND RESPIRATORY TRACT. MAY CAUSE ALLERGIC SKIN OR RESPIRATORY REACTION. CANCER HAZARD. CAN CAUSE CANCER. Risk of cancer depends on duration and level of exposure. Very toxic to aquatic organisms; may cause long term adverse effects in the aquatic environment. SAF-T-DATA(tm) Ratings (Provided here for your convenience) ----------------------------------------------------------------------------------------------------------- Health Rating: 3 - Severe (Cancer Causing) Flammability Rating: 0 - None Reactivity Rating: 3 - Severe (Oxidizer) Contact Rating: 3 - Severe (Life) Lab Protective Equip: GOGGLES & SHIELD; LAB COAT & APRON; VENT

150

Appendix B (Continued) HOOD; PROPER GLOVES Storage Color Code: Yellow (Reactive) ----------------------------------------------------------------------------------------------------------- Potential Health Effects ---------------------------------- Inhalation: Causes irritation to the respiratory tract. Symptoms may include coughing, sore throat, and shortness of breath. Lung damage may result from a single high exposure or lower repeated exposures. Lung allergy occasionally occurs, with asthma type symptoms. Ingestion: Toxic. Symptoms may include abdominal pain, diarrhea, nausea, and vomiting. Absorption is poor, but should it occur, symptoms may include giddiness, capillary damage, myocardial weakness, central nervous system depression, and kidney and liver damage. Skin Contact: Causes irritation. May cause skin allergy with itching, redness or rash. Some individuals may become sensitized to the substance and suffer "nickel itch", a form of dermatitis. Eye Contact: Causes irritation, redness, and pain. Chronic Exposure: Prolonged or repeated exposure to excessive concentrations may affect lungs, liver and kidneys. Chronic exposure to nickel and nickel compounds is associated with cancer. Aggravation of Pre-existing Conditions: Persons with pre-existing skin disorders, impaired respiratory or pulmonary function, or with a history of asthma, allergies, or sensitization to nickel compounds may be at an increased risk upon exposure to this substance.

4. First Aid Measures Inhalation: Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical attention. Ingestion: Induce vomiting immediately as directed by medical personnel. Never give anything by mouth to an unconscious person. Get medical attention.

151

Appendix B (Continued) Skin Contact: Wipe off excess material from skin then immediately flush skin with plenty of water for at least 15 minutes. Remove contaminated clothing and shoes. Get medical attention. Wash clothing before reuse. Thoroughly clean shoes. Eye Contact: Immediately flush eyes with plenty of water for at least 15 minutes, lifting lower and upper eyelids occasionally. Get medical attention immediately.

5. Fire Fighting Measures Fire: Not combustible, but substance is a strong oxidizer and its heat of reaction with reducing agents or combustibles may cause ignition. Increases the flammability of any combustible material. Explosion: Contact with oxidizable substances may cause extremely violent combustion. Strong oxidants may explode when shocked, or if exposed to heat, flame, or friction. Also may act as initiation source for dust or vapor explosions. Fire Extinguishing Media: Water or water spray in early stages of fire. Foam or dry chemical may also be used. Special Information: Wear full protective clothing and breathing equipment for high-intensity fire or potential explosion conditions.

6. Accidental Release Measures Remove all sources of ignition. Ventilate area of leak or spill. Wear appropriate personal protective equipment as specified in Section 8. Spills: Clean up spills in a manner that does not disperse dust into the air. Use non-sparking tools and equipment. Reduce airborne dust and prevent scattering by moistening with water. Pick up spill for recovery or disposal and place in a closed container.

7. Handling and Storage Keep in a tightly closed container, stored in a cool, dry, ventilated area. Protect against physical damage and moisture. Isolate from any source of heat or ignition. Avoid storage on wood floors. Separate from incompatibles, combustibles, organic or other readily oxidizable materials. Areas in which exposure to nickel metal or soluble nickel compounds may occur should be identified by signs or appropriate means, and access to the area should be limited to authorized persons. Containers of this material may be hazardous when empty since they retain product residues (dust, solids); observe all warnings and precautions listed for the product.

152

Appendix B (Continued) 8. Exposure Controls/Personal Protection Airborne Exposure Limits: -OSHA Permissible Exposure Limit (PEL): soluble Nickel compounds as Ni: 1 mg/m3 (TWA) -ACGIH Threshold Limit Value (TLV): soluble Nickel compounds as Ni: 0.1 mg/m3 (TWA), A4 - Not classifiable as a human carcinogen Ventilation System: A system of local and/or general exhaust is recommended to keep employee exposures below the Airborne Exposure Limits. Local exhaust ventilation is generally preferred because it can control the emissions of the contaminant at its source, preventing dispersion of it into the general work area. Please refer to the ACGIH document, Industrial Ventilation, A Manual of Recommended Practices, most recent edition, for details. Personal Respirators (NIOSH Approved): If the exposure limit is exceeded and engineering controls are not feasible, a full facepiece particulate respirator (NIOSH type N100 filters) may be worn for up to 50 times the exposure limit or the maximum use concentration specified by the appropriate regulatory agency or respirator supplier, whichever is lowest. If oil particles (e.g. lubricants, cutting fluids. glycerine, etc.) are present, use a NIOSH type R or P filter. For emergencies or instances where the exposure levels are not known, use a full-facepiece positive-pressure, air-supplied respirator. WARNING: Air-purifying respirators do not protect workers in oxygen-deficient atmospheres. Skin Protection: Rubber or neoprene gloves and additional protection including impervious boots, apron, or coveralls, as needed in areas of unusual exposure. Eye Protection: Use chemical safety goggles and/or full face shield where dusting or splashing of solutions is possible. Maintain eye wash fountain and quick-drench facilities in work area. Other Control Measures: Eating, drinking, and smoking should not be permitted in areas where solids or liquids containing soluble nickel compounds are handled, processed, or stored. NIOSH recommends pre-placement and periodic medical exams, with maintaining of records for all employees exposed to nickel in the workplace.

9. Physical and Chemical Properties Appearance: Green, transparent crystals. Odor: Odorless.

153

Appendix B (Continued) Solubility: 238.5g/100cc water @ 0C Specific Gravity: 2.05 pH: 3.5 - 5.5 (5% solution @ 25C (77F). % Volatiles by volume @ 21C (70F): 0 Boiling Point: 137C (279F) Melting Point: 56.7C (135F) Vapor Density (Air=1): No information found. Vapor Pressure (mm Hg): 0 @ 20C (68F) Evaporation Rate (BuAc=1): No information found.

10. Stability and Reactivity Stability: Stable under ordinary conditions of use and storage. Substance has both oxidant and reducing characteristics, and is unstable when heated or shocked. Hazardous Decomposition Products: Emits toxic fumes of nickel and nitrogen oxides when heated to decomposition. Hazardous Polymerization: Will not occur. Incompatibilities: Aluminum, boron phosphide, cyanides, esters, combustible material, phospham, phosphorus, sodium hypophosphite, stannous chloride, thiocyanates, strong reducing agents, and organic materials. Conditions to Avoid: Heat, shock, friction, incompatibles.

154

Appendix B (Continued) 11. Toxicological Information Nickelous Nitrate Hexahydrate; Oral rat LD50: 1620 mg/kg. Investigated as a tumorigen. --------\Cancer Lists\------------------------------------------------------ ---NTP Carcinogen--- Ingredient Known Anticipated IARC Category ------------------------------------ ----- ----------- ------------- Nickel Nitrate (13138-45-9) Yes No 1

12. Ecological Information Environmental Fate: When released into water, this material is not expected to evaporate significantly. This material is not expected to significantly bioaccumulate. Environmental Toxicity: Dangerous to the environment. Very toxic to aquatic organisms; may cause long term adverse effects in the aquatic environment.

13. Disposal Considerations Whatever cannot be saved for recovery or recycling should be handled as hazardous waste and sent to a RCRA approved waste facility. Processing, use or contamination of this product may change the waste management options. State and local disposal regulations may differ from federal disposal regulations. Dispose of container and unused contents in accordance with federal, state and local requirements.

14. Transport Informatio=p Domestic (Land, D.O.T.) ----------------------- Proper Shipping Name: NICKEL NITRATE Hazard Class: 5.1 UN/NA: UN2725 Packing Group: III Information reported for product/size: 4X25LB International (Water, I.M.O.) ----------------------------- Proper Shipping Name: NICKEL NITRATE Hazard Class: 5.1 UN/NA: UN2725 Packing Group: III Information reported for product/size: 4X25LB

155

Appendix B (Continued) 15. Regulatory Information --------\Chemical Inventory Status - Part 1\--------------------------------- Ingredient TSCA EC Japan Australia ----------------------------------------------- ---- --- ----- --------- Nickel Nitrate (13138-45-9) Yes Yes Yes Yes --------\Chemical Inventory Status - Part 2\--------------------------------- --Canada-- Ingredient Korea DSL NDSL Phil. ----------------------------------------------- ----- --- ---- ----- Nickel Nitrate (13138-45-9) Yes Yes No Yes --------\Federal, State & International Regulations - Part 1\---------------- -SARA 302- ------SARA 313------ Ingredient RQ TPQ List Chemical Catg. ----------------------------------------- --- ----- ---- -------------- Nickel Nitrate (13138-45-9) No No No Nickel cmpd/ --------\Federal, State & International Regulations - Part 2\---------------- -RCRA- -TSCA- Ingredient CERCLA 261.33 8(d) ----------------------------------------- ------ ------ ------ Nickel Nitrate (13138-45-9) No No No Chemical Weapons Convention: No TSCA 12(b): No CDTA: No SARA 311/312: Acute: Yes Chronic: Yes Fire: No Pressure: No Reactivity: Yes (Pure / Solid) WARNING: THIS PRODUCT CONTAINS A CHEMICAL(S) KNOWN TO THE STATE OF CALIFORNIA TO CAUSE CANCER. Australian Hazchem Code: 1Y Poison Schedule: None allocated. WHMIS: This MSDS has been prepared according to the hazard criteria of the Controlled Products Regulations (CPR) and the MSDS contains all of the information required by the CPR.

156

157

Appendix B (Continued) 16. Other Information NFPA Ratings: Health: 1 Flammability: 0 Reactivity: 0 Other: Oxidizer Label Hazard Warning: DANGER! STRONG OXIDIZER. CONTACT WITH OTHER MATERIAL MAY CAUSE FIRE. HARMFUL IF SWALLOWED OR INHALED. CAUSES IRRITATION TO SKIN, EYES AND RESPIRATORY TRACT. MAY CAUSE ALLERGIC SKIN OR RESPIRATORY REACTION. CANCER HAZARD. CAN CAUSE CANCER. Risk of cancer depends on duration and level of exposure. Very toxic to aquatic organisms; may cause long term adverse effects in the aquatic environment. Label Precautions: Do not store near combustible materials. Do not get in eyes, on skin, or on clothing. Remove and wash contaminated clothing promptly. Wash thoroughly after handling. Do not breathe dust. Keep container closed. Use only with adequate ventilation. Avoid release to the environment. Label First Aid: If swallowed, induce vomiting immediately as directed by medical personnel. Never give anything by mouth to an unconscious person. If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. In case of contact, wipe off excess material from skin then immediately flush eyes or skin with plenty of water for at least 15 minutes. Remove contaminated clothing and shoes. Wash clothing before reuse. In all cases, get medical attention. Product Use: Laboratory Reagent. Revision Information: MSDS Section(s) changed since last revision of document include: 3, 11, 12, 16.

Appendix B (Continued)

B.7. Nitric Acid

General Synonyms: azotic acid, aqua fortis Molecular formula: HNO3 CAS No: 7697-37-2 EC No: 231-714-2 Physical data Appearance: colourless liquid with a choking odour Melting point: -42 C Boiling point: 121 C (69% boils at ca. 86C) Specific gravity: 1.41 Vapour pressure: 62 mm Hg at 20 C (68%) Flash point: Explosion limits: Autoignition temperature: Stability Stable. Strong oxidizer. Substances to be avoided include strong bases, strong reducing agents, alkalis, most common metals, organic materials, alcohols, carbides. Corrodes steel. Light-sensitive. Toxicology May be fatal if swallowed or inhaled. Extremely corrosive. Contact with skin or eyes may cause severe burns and permanent damage. TLV 2 ppm. OES long-term 5 mg/m3 Toxicity data (The meaning of any abbreviations which appear in this section is given here.) IHL-RAT LC50 244 ppm (NO2)/30m ORL-HMN LDLO 430 mg kg-1 Risk phrases (The meaning of any risk phrases which appear in this section is given here.) R8 R23 R24 R25 R34 R41. Transport information (The meaning of any UN hazard codes which appear in this section is given here.) UN No 2031. Packing group II. Hazard class 8.0. Transport category 2. Personal protection Safety glasses or face mask, gloves. Fume cupboard. Safety phrases (The meaning of any safety phrases which appear in this section is given here.) S23 S26 S36 S37 S39 S45.

158

Appendix B (Continued)

B.8. Sodium Hdyroxide

SODIUM HYDROXIDE MSDS Number: S4034 --- Effective Date: 03/05/97

1. Product Identification Synonyms: Caustic soda; lye; sodium hydroxide solid; sodium hydrate CAS No.: 1310-73-2 Molecular Weight: 40.00 Chemical Formula: NaOH Product Codes: J.T. Baker: 3718, 3721, 3722, 3723, 3728, 3729, 3734, 3736, 5045, 5565 Mallinckrodt: 7001, 7680, 7708, 7712, 7772, 7798

2. Composition/Information on Ingredients Ingredient CAS No Percent Hazardous --------------------------------------- ------------ ------- --------- Sodium Hydroxide 1310-73-2 99 - 100% Yes

3. Hazards Identification

159

Emergency Overview -------------------------- POISON! DANGER! CORROSIVE. MAY BE FATAL IF SWALLOWED. HARMFUL IF INHALED. CAUSES BURNS TO ANY AREA OF CONTACT. REACTS WITH WATER, ACIDS AND OTHER MATERIALS. J.T. Baker SAF-T-DATA(tm) Ratings (Provided here for your convenience) ----------------------------------------------------------------------------------------------------------- Health Rating: 3 - Severe (Poison) Flammability Rating: 0 - None Reactivity Rating: 2 - Moderate Contact Rating: 4 - Extreme (Corrosive) Lab Protective Equip: GOGGLES; LAB COAT; VENT HOOD; PROPER GLOVES Storage Color Code: White Stripe (Store Separately) -----------------------------------------------------------------------------------------------------------

Appendix B (Continued) Potential Health Effects ---------------------------------- Inhalation: Severe irritant. Effects from inhalation of dust or mist vary from mild irritation to serious damage of the upper respiratory tract, depending on severity of exposure. Symptoms may include sneezing, sore throat or runny nose. Severe pneumonitis may occur. Ingestion: Corrosive! Swallowing may cause severe burns of mouth, throat, and stomach. Severe scarring of tissue and death may result. Symptoms may include bleeding, vomiting, diarrhea, fall in blood pressure. Damage may appears days after exposure. Skin Contact: Corrosive! Contact with skin can cause irritation or severe burns and scarring with greater exposures. Eye Contact: Corrosive! Causes irritation of eyes, and with greater exposures it can cause burns that may result in permanent impairment of vision, even blindness. Chronic Exposure: Prolonged contact with dilute solutions or dust has a destructive effect upon tissue. Aggravation of Pre-existing Conditions: Persons with pre-existing skin disorders or eye problems or impaired respiratory function may be more susceptible to the effects of the substance.

4. First Aid Measures Inhalation: Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Call a physician. Ingestion: DO NOT INDUCE VOMITING! Give large quantities of water or milk if available. Never give anything by mouth to an unconscious person. Get medical attention immediately.

160

Appendix B (Continued) Skin Contact: Immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Call a physician, immediately. Wash clothing before reuse. Eye Contact: Immediately flush eyes with plenty of water for at least 15 minutes, lifting lower and upper eyelids occasionally. Get medical attention immediately. Note to Physician: Perform endoscopy in all cases of suspected sodium hydroxide ingestion. In cases of severe esophageal corrosion, the use of therapeutic doses of steroids should be considered. General supportive measures with continual monitoring of gas exchange, acid-base balance, electrolytes, and fluid intake are also required.

5. Fire Fighting Measures Fire: Not considered to be a fire hazard. Hot or molten material can react violently with water. Can react with certain metals, such as aluminum, to generate flammable hydrogen gas. Explosion: Not considered to be an explosion hazard. Fire Extinguishing Media: Use any means suitable for extinguishing surrounding fire. Adding water to caustic solution generates large amounts of heat. Special Information: In the event of a fire, wear full protective clothing and NIOSH-approved self-contained breathing apparatus with full facepiece operated in the pressure demand or other positive pressure mode.

161

Appendix B (Continued) 6. Accidental Release Measures Ventilate area of leak or spill. Keep unnecessary and unprotected people away from area of spill. Wear appropriate personal protective equipment as specified in Section 8. Spills: Pick up and place in a suitable container for reclamation or disposal, using a method that does not generate dust. Do not flush caustic residues to the sewer. Residues from spills can be diluted with water, neutralized with dilute acid such as acetic, hydrochloric or sulfuric. Absorb neutralized caustic residue on clay, vermiculite or other inert substance and package in a suitable container for disposal. US Regulations (CERCLA) require reporting spills and releases to soil, water and air in excess of reportable quantities. The toll free number for the US Coast Guard National Response Center is (800) 424-8802.

7. Handling and Storage Keep in a tightly closed container. Protect from physical damage. Store in a cool, dry, ventilated area away from sources of heat, moisture and incompatibilities. Always add the caustic to water while stirring; never the reverse. Containers of this material may be hazardous when empty since they retain product residues (dust, solids); observe all warnings and precautions listed for the product. Do not store with aluminum or magnesium. Do not mix with acids or organic materials.

8. Exposure Controls/Personal Protection Airborne Exposure Limits: - OSHA Permissible Exposure Limit (PEL): 2 mg/m3 Ceiling - ACGIH Threshold Limit Value (TLV): 2 mg/m3 Ceiling Ventilation System: A system of local and/or general exhaust is recommended to keep employee exposures below the Airborne Exposure Limits. Local exhaust ventilation is generally preferred because it can control the emissions of the contaminant at its source, preventing dispersion of it into the general work area. Please refer to the ACGIH document, Industrial Ventilation, A Manual of Recommended Practices, most recent edition, for details.

162

Appendix B (Continued) Personal Respirators (NIOSH Approved): If the exposure limit is exceeded, a half-face dust/mist respirator may be worn for up to ten times the exposure limit or the maximum use concentration specified by the appropriate regulatory agency or respirator supplier, whichever is lowest. A full-face piece dust/mist respirator may be worn up to 50 times the exposure limit, or the maximum use concentration specified by the appropriate regulatory agency, or respirator supplier, whichever is lowest. For emergencies or instances where the exposure levels are not known, use a full-facepiece positive-pressure, air-supplied respirator. WARNING: Air-purifying respirators do not protect workers in oxygen-deficient atmospheres. Skin Protection: Wear impervious protective clothing, including boots, gloves, lab coat, apron or coveralls, as appropriate, to prevent skin contact. Eye Protection: Use chemical safety goggles and/or a full face shield where splashing is possible. Maintain eye wash fountain and quick-drench facilities in work area.

9. Physical and Chemical Properties Appearance: White, deliquescent pellets. Odor: Odorless. Solubility: 111 g/100 g of water. Specific Gravity: 2.13 pH: 13 - 14 (0.5% soln.) % Volatiles by volume @ 21C (70F): 0 Boiling Point: 1390C (2534F)

163

Appendix B (Continued) Melting Point: 318C (604F) Vapor Density (Air=1): > 1.0 Vapor Pressure (mm Hg): Negligible. Evaporation Rate (BuAc=1): No information found.

10. Stability and Reactivity Stability: Stable under ordinary conditions of use and storage. Very hygroscopic. Can slowly pick up moisture from air and react with carbon dioxide from air to form sodium carbonate. Hazardous Decomposition Products: Sodium oxide. Decomposition by reaction with certain metals releases flammable and explosive hydrogen gas. Hazardous Polymerization: Will not occur. Incompatibilities: Contact with water, acids, flammable liquids, and organic halogen compounds, especially trichloroethylene, may cause fire or explosion. Contact with nitromethane and other similar nitro compounds causes formation of shock-sensitive salts. Contact with metals such as aluminum, tin, and zinc causes formation of flammable hydrogen gas. Conditions to Avoid: Moisture, dusting and incompatibles.

164

Appendix B (Continued) 11. Toxicological Information Irritation data: skin, rabbit: 500 mg/24H severe; eye rabbit: 50 ug/24H severe; investigated as a mutagen. --------\Cancer Lists\------------------------------------------------------ ---NTP Carcinogen--- Ingredient Known Anticipated IARC Category ------------------------------------ ----- ----------- ------------- Sodium Hydroxide (1310-73-2) No No None

12. Ecological Information Environmental Fate: No information found. Environmental Toxicity: No information found.

13. Disposal Considerations Whatever cannot be saved for recovery or recycling should be handled as hazardous waste and sent to a RCRA approved waste facility. Processing, use or contamination of this product may change the waste management options. State and local disposal regulations may differ from federal disposal regulations. Dispose of container and unused contents in accordance with federal, state and local requirements.

14. Transport Information Domestic (Land, D.O.T.) ----------------------- Proper Shipping Name: SODIUM HYDROXIDE, SOLID Hazard Class: 8 UN/NA: UN1823 Packing Group: II Information reported for product/size: 300LB International (Water, I.M.O.) ----------------------------- Proper Shipping Name: SODIUM HYDROXIDE, SOLID Hazard Class: 8 UN/NA: UN1823 Packing Group: II Information reported for product/size: 300LB

165

Appendix B (Continued) 15. Regulatory Information --------\Chemical Inventory Status - Part 1\--------------------------------- Ingredient TSCA EC Japan Australia ----------------------------------------------- ---- --- ----- --------- Sodium Hydroxide (1310-73-2) Yes Yes Yes Yes --------\Chemical Inventory Status - Part 2\--------------------------------- --Canada-- Ingredient Korea DSL NDSL Phil. ----------------------------------------------- ----- --- ---- ----- Sodium Hydroxide (1310-73-2) Yes Yes No Yes --------\Federal, State & International Regulations - Part 1\---------------- -SARA 302- ------SARA 313------ Ingredient RQ TPQ List Chemical Catg. ----------------------------------------- --- ----- ---- -------------- Sodium Hydroxide (1310-73-2) No No Yes No --------\Federal, State & International Regulations - Part 2\---------------- -RCRA- -TSCA- Ingredient CERCLA 261.33 8(d) ----------------------------------------- ------ ------ ------ Sodium Hydroxide (1310-73-2) 1000 No No Chemical Weapons Convention: No TSCA 12(b): No CDTA: No SARA 311/312: Acute: Yes Chronic: No Fire: No Pressure: No Reactivity: Yes (Pure / Solid) Australian Hazchem Code: 2R Poison Schedule: S6 WHMIS: This MSDS has been prepared according to the hazard criteria of the Controlled Products Regulations (CPR) and the MSDS contains all of the information required by the CPR.

166

167

Appendix B (Continued) 16. Other Information NFPA Ratings: Health: 3 Flammability: 0 Reactivity: 1 Label Hazard Warning: POISON! DANGER! CORROSIVE. MAY BE FATAL IF SWALLOWED. HARMFUL IF INHALED. CAUSES BURNS TO ANY AREA OF CONTACT. REACTS WITH WATER, ACIDS AND OTHER MATERIALS. Label Precautions: Do not get in eyes, on skin, or on clothing. Do not breathe dust. Keep container closed. Use only with adequate ventilation. Wash thoroughly after handling. Label First Aid: If swallowed, DO NOT INDUCE VOMITING. Give large quantities of water. Never give anything by mouth to an unconscious person. In case of contact, immediately flush eyes or skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse. If inhaled, remove to fresh air. If not breathing give artificial respiration. If breathing is difficult, give oxygen. In all cases get medical attention immediately. Product Use: Laboratory Reagent. Revision Information: Pure. New 16 section MSDS format, all sections have been revised.